Publications by authors named "Stanislav Kmoch"

94 Publications

Biallelic loss-of-function variants in PLD1 cause congenital right-sided cardiac valve defects and neonatal cardiomyopathy.

J Clin Invest 2021 03;131(5)

Amsterdam UMC, University of Amsterdam, Heart Center, Department of Clinical and Experimental Cardiology, Amsterdam Cardiovascular Sciences.

Congenital heart disease is the most common type of birth defect, accounting for one-third of all congenital anomalies. Using whole-exome sequencing of 2718 patients with congenital heart disease and a search in GeneMatcher, we identified 30 patients from 21 unrelated families of different ancestries with biallelic phospholipase D1 (PLD1) variants who presented predominantly with congenital cardiac valve defects. We also associated recessive PLD1 variants with isolated neonatal cardiomyopathy. Furthermore, we established that p.I668F is a founder variant among Ashkenazi Jews (allele frequency of ~2%) and describe the phenotypic spectrum of PLD1-associated congenital heart defects. PLD1 missense variants were overrepresented in regions of the protein critical for catalytic activity, and, correspondingly, we observed a strong reduction in enzymatic activity for most of the mutant proteins in an enzymatic assay. Finally, we demonstrate that PLD1 inhibition decreased endothelial-mesenchymal transition, an established pivotal early step in valvulogenesis. In conclusion, our study provides a more detailed understanding of disease mechanisms and phenotypic expression associated with PLD1 loss of function.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1172/JCI142148DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7919725PMC
March 2021

POLRMT mutations impair mitochondrial transcription causing neurological disease.

Nat Commun 2021 02 18;12(1):1135. Epub 2021 Feb 18.

Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.

While >300 disease-causing variants have been identified in the mitochondrial DNA (mtDNA) polymerase γ, no mitochondrial phenotypes have been associated with POLRMT, the RNA polymerase responsible for transcription of the mitochondrial genome. Here, we characterise the clinical and molecular nature of POLRMT variants in eight individuals from seven unrelated families. Patients present with global developmental delay, hypotonia, short stature, and speech/intellectual disability in childhood; one subject displayed an indolent progressive external ophthalmoplegia phenotype. Massive parallel sequencing of all subjects identifies recessive and dominant variants in the POLRMT gene. Patient fibroblasts have a defect in mitochondrial mRNA synthesis, but no mtDNA deletions or copy number abnormalities. The in vitro characterisation of the recombinant POLRMT mutants reveals variable, but deleterious effects on mitochondrial transcription. Together, our in vivo and in vitro functional studies of POLRMT variants establish defective mitochondrial transcription as an important disease mechanism.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41467-021-21279-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7893070PMC
February 2021

The Varied Clinical Presentation of Autosomal Dominant Tubulointerstitial Kidney Disease Due to Mutations.

Kidney Int Rep 2020 Dec 21;5(12):2133-2135. Epub 2020 Oct 21.

Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, NC, USA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ekir.2020.10.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710887PMC
December 2020

Ntrk1 mutation co-segregating with bipolar disorder and inherited kidney disease in a multiplex family causes defects in neuronal growth and depression-like behavior in mice.

Transl Psychiatry 2020 11 24;10(1):407. Epub 2020 Nov 24.

Department of Psychiatry, University of California San Diego, San Diego, USA.

Previously, we reported a family in which bipolar disorder (BD) co-segregates with a Mendelian kidney disorder linked to 1q22. The causative renal gene was later identified as MUC1. Genome-wide linkage analysis of BD in the family yielded a peak at 1q22 that encompassed the NTRK1 and MUC1 genes. NTRK1 codes for TrkA (Tropomyosin-related kinase A) which is essential for development of the cholinergic nervous system. Whole genome sequencing of the proband identified a damaging missense mutation, E492K, in NTRK1. Induced pluripotent stem cells were generated from family members, and then differentiated to neural stem cells (NSCs). E492K NSCs had reduced neurite outgrowth. A conditional knock-in mouse line, harboring the point mutation in the brain, showed depression-like behavior in the tail suspension test following challenge by physostigmine, a cholinesterase inhibitor. These results are consistent with the cholinergic hypothesis of depression. They imply that the NTRK1 E492K mutation, impairs cholinergic neurotransmission, and may convey susceptibility to bipolar disorder.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41398-020-01087-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7687911PMC
November 2020

Genetic and Clinical Predictors of Age of ESKD in Individuals With Autosomal Dominant Tubulointerstitial Kidney Disease Due to Mutations.

Kidney Int Rep 2020 Sep 3;5(9):1472-1485. Epub 2020 Jul 3.

Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA.

Introduction: Autosomal dominant tubulo-interstitial kidney disease due to mutations (ADTKD-) is a rare condition associated with high variability in the age of end-stage kidney disease (ESKD). The minor allele of rs4293393, located in the promoter of the gene, is present in 19% of the population and downregulates uromodulin production by approximately 50% and might affect the age of ESKD. The goal of this study was to better understand the genetic and clinical characteristics of ADTKD- and to perform a Mendelian randomization study to determine if the minor allele of rs4293393 was associated with better kidney survival.

Methods: An international group of collaborators collected clinical and genetic data on 722 affected individuals from 249 families with 125 mutations, including 28 new mutations. The median age of ESKD was 47 years. Men were at a much higher risk of progression to ESKD (hazard ratio 1.78,  < 0.001).

Results: The allele frequency of the minor rs4293393 allele was only 11.6% versus the 19% expected ( < 0.01), resulting in Hardy-Weinberg disequilibrium and precluding a Mendelian randomization experiment. An score reflecting the severity of the trafficking defect of uromodulin mutants was found to be a promising predictor of the age of ESKD.

Conclusion: We report the clinical characteristics associated with 125 mutations. Male gender and a new score predict age of ESKD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ekir.2020.06.029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7486199PMC
September 2020

NOTCH2NLC CGG Repeats Are Not Expanded and Skin Biopsy Was Negative in an Infantile Patient With Neuronal Intranuclear Inclusion Disease.

J Neuropathol Exp Neurol 2020 10;79(10):1065-1071

Department of Pediatrics and Adolescent Medicine, Research Unit for Rare Diseases.

Neuronal intranuclear inclusion disease (NIID) is a progressive neurodegenerative disorder categorized into 3 phenotypic variants: infantile, juvenile, and adult. Four recent reports have linked NIID to CGG expansions in the NOTCH2NLC gene in adult NIID (aNIID) and several juvenile patients. Infantile NIID (iNIID) is an extremely rare neuropediatric condition. We present a 7-year-old male patient with severe progressive neurodegenerative disease that included cerebellar symptoms with cerebellar atrophy on brain MRI, psychomotor developmental regression, pseudobulbar syndrome, and polyneuropathy. The diagnosis of iNIID was established through a postmortem neuropathology work-up. We performed long-read sequencing of the critical NOTCH2NLC repeat motif and found no expansion in the patient. We also re-evaluated an antemortem skin biopsy that was collected when the patient was 2 years and 8 months old and did not identify the intranuclear inclusions. In our report, we highlight that the 2 methods (skin biopsy and CGG expansion testing in NOTCH2NLC) used to identify aNIID patients may provide negative results in iNIID patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/jnen/nlaa070DOI Listing
October 2020

Biallelic MADD variants cause a phenotypic spectrum ranging from developmental delay to a multisystem disorder.

Brain 2020 08;143(8):2437-2453

Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.

In pleiotropic diseases, multiple organ systems are affected causing a variety of clinical manifestations. Here, we report a pleiotropic disorder with a unique constellation of neurological, endocrine, exocrine, and haematological findings that is caused by biallelic MADD variants. MADD, the mitogen-activated protein kinase (MAPK) activating death domain protein, regulates various cellular functions, such as vesicle trafficking, activity of the Rab3 and Rab27 small GTPases, tumour necrosis factor-α (TNF-α)-induced signalling and prevention of cell death. Through national collaboration and GeneMatcher, we collected 23 patients with 21 different pathogenic MADD variants identified by next-generation sequencing. We clinically evaluated the series of patients and categorized the phenotypes in two groups. Group 1 consists of 14 patients with severe developmental delay, endo- and exocrine dysfunction, impairment of the sensory and autonomic nervous system, and haematological anomalies. The clinical course during the first years of life can be potentially fatal. The nine patients in Group 2 have a predominant neurological phenotype comprising mild-to-severe developmental delay, hypotonia, speech impairment, and seizures. Analysis of mRNA revealed multiple aberrant MADD transcripts in two patient-derived fibroblast cell lines. Relative quantification of MADD mRNA and protein in fibroblasts of five affected individuals showed a drastic reduction or loss of MADD. We conducted functional tests to determine the impact of the variants on different pathways. Treatment of patient-derived fibroblasts with TNF-α resulted in reduced phosphorylation of the extracellular signal-regulated kinases 1 and 2, enhanced activation of the pro-apoptotic enzymes caspase-3 and -7 and increased apoptosis compared to control cells. We analysed internalization of epidermal growth factor in patient cells and identified a defect in endocytosis of epidermal growth factor. We conclude that MADD deficiency underlies multiple cellular defects that can be attributed to alterations of TNF-α-dependent signalling pathways and defects in vesicular trafficking. Our data highlight the multifaceted role of MADD as a signalling molecule in different organs and reveal its physiological role in regulating the function of the sensory and autonomic nervous system and endo- and exocrine glands.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/brain/awaa204DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7447524PMC
August 2020

An international cohort study of autosomal dominant tubulointerstitial kidney disease due to REN mutations identifies distinct clinical subtypes.

Kidney Int 2020 12 1;98(6):1589-1604. Epub 2020 Aug 1.

Research Unit of Rare Diseases, Department of Pediatric and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic; Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA. Electronic address:

There have been few clinical or scientific reports of autosomal dominant tubulointerstitial kidney disease due to REN mutations (ADTKD-REN), limiting characterization. To further study this, we formed an international cohort characterizing 111 individuals from 30 families with both clinical and laboratory findings. Sixty-nine individuals had a REN mutation in the signal peptide region (signal group), 27 in the prosegment (prosegment group), and 15 in the mature renin peptide (mature group). Signal group patients were most severely affected, presenting at a mean age of 19.7 years, with the prosegment group presenting at 22.4 years, and the mature group at 37 years. Anemia was present in childhood in 91% in the signal group, 69% prosegment, and none of the mature group. REN signal peptide mutations reduced hydrophobicity of the signal peptide, which is necessary for recognition and translocation across the endoplasmic reticulum, leading to aberrant delivery of preprorenin into the cytoplasm. REN mutations in the prosegment led to deposition of prorenin and renin in the endoplasmic reticulum-Golgi intermediate compartment and decreased prorenin secretion. Mutations in mature renin led to deposition of the mutant prorenin in the endoplasmic reticulum, similar to patients with ADTKD-UMOD, with a rate of progression to end stage kidney disease (63.6 years) that was significantly slower vs. the signal (53.1 years) and prosegment groups (50.8 years) (significant hazard ratio 0.367). Thus, clinical and laboratory studies revealed subtypes of ADTKD-REN that are pathophysiologically, diagnostically, and clinically distinct.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.kint.2020.06.041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7719087PMC
December 2020

Clinical and genetic spectra of autosomal dominant tubulointerstitial kidney disease due to mutations in UMOD and MUC1.

Kidney Int 2020 09 22;98(3):717-731. Epub 2020 May 22.

Institute of Physiology, University of Zurich, Zurich, Switzerland; Division of Nephrology, Cliniques Universitaires Saint-Luc, Brussels, Belgium. Electronic address:

Autosomal dominant tubulointerstitial kidney disease (ADTKD) is an increasingly recognized cause of end-stage kidney disease, primarily due to mutations in UMOD and MUC1. The lack of clinical recognition and the small size of cohorts have slowed the understanding of disease ontology and development of diagnostic algorithms. We analyzed two registries from Europe and the United States to define genetic and clinical characteristics of ADTKD-UMOD and ADTKD-MUC1 and develop a practical score to guide genetic testing. Our study encompassed 726 patients from 585 families with a presumptive diagnosis of ADTKD along with clinical, biochemical, genetic and radiologic data. Collectively, 106 different UMOD mutations were detected in 216/562 (38.4%) of families with ADTKD (303 patients), and 4 different MUC1 mutations in 72/205 (35.1%) of the families that are UMOD-negative (83 patients). The median kidney survival was significantly shorter in patients with ADTKD-MUC1 compared to ADTKD-UMOD (46 vs. 54 years, respectively), whereas the median gout-free survival was dramatically reduced in patients with ADTKD-UMOD compared to ADTKD-MUC1 (30 vs. 67 years, respectively). In contrast to patients with ADTKD-UMOD, patients with ADTKD-MUC1 had normal urinary excretion of uromodulin and distribution of uromodulin in tubular cells. A diagnostic algorithm based on a simple score coupled with urinary uromodulin measurements separated patients with ADTKD-UMOD from those with ADTKD-MUC1 with a sensitivity of 94.1%, a specificity of 74.3% and a positive predictive value of 84.2% for a UMOD mutation. Thus, ADTKD-UMOD is more frequently diagnosed than ADTKD-MUC1, ADTKD subtypes present with distinct clinical features, and a simple score coupled with urine uromodulin measurements may help prioritizing genetic testing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.kint.2020.04.038DOI Listing
September 2020

Spinal muscular atrophy caused by a novel Alu-mediated deletion of exons 2a-5 in SMN1 undetectable with routine genetic testing.

Mol Genet Genomic Med 2020 07 26;8(7):e1238. Epub 2020 Apr 26.

Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic.

Background: Spinal muscular atrophy (SMA) is an inherited neuromuscular disease affecting 1 in 8,000 newborns. The majority of patients carry bi-allelic variants in the survival of motor neuron 1 gene (SMN1). SMN1 is located in a duplicated region on chromosome 5q13 that contains Alu elements and is predisposed to genomic rearrangements. Due to the genomic complexity of the SMN region and genetic heterogeneity, approximately 50% of SMA patients remain without genetic diagnosis that is a prerequisite for genetic treatments. In this work we describe the diagnostic odyssey of one SMA patient in whom routine diagnostics identified only a maternal heterozygous SMN1Δ(7-8) deletion.

Methods: We characterized SMN transcripts, assessed SMN protein content in peripheral blood mononuclear cells (PBMC), estimated SMN genes dosage, and mapped genomic rearrangement in the SMN region.

Results: We identified an Alu-mediated deletion encompassing exons 2a-5 of SMN1 on the paternal allele and a complete deletion of SMN1 on the maternal allele as the cause of SMA in this patient.

Conclusion: Alu-mediated rearrangements in SMN1 can escape routine diagnostic testing. Parallel analysis of SMN gene dosage, SMN transcripts, and total SMN protein levels in PBMC can identify genomic rearrangements and should be considered in genetically undefined SMA cases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mgg3.1238DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7336725PMC
July 2020

Multigene Panel Germline Testing of 1333 Czech Patients with Ovarian Cancer.

Cancers (Basel) 2020 Apr 13;12(4). Epub 2020 Apr 13.

Institute of Biochemistry and Experimental Oncology, First Faculty of Medicine, Charles University, 128 53 Prague, Czech Republic.

Ovarian cancer (OC) is the deadliest gynecologic malignancy with a substantial proportion of hereditary cases and a frequent association with breast cancer (BC). Genetic testing facilitates treatment and preventive strategies reducing OC mortality in mutation carriers. However, the prevalence of germline mutations varies among populations and many rarely mutated OC predisposition genes remain to be identified. We aimed to analyze 219 genes in 1333 Czech OC patients and 2278 population-matched controls using next-generation sequencing. We revealed germline mutations in 18 OC/BC predisposition genes in 32.0% of patients and in 2.5% of controls. Mutations in , , , and mismatch repair genes conferred high OC risk (OR > 5). Mutations in and were associated with moderate risk (both OR = 3.5). mutations dominated in almost all clinicopathological subgroups including sporadic borderline tumors of ovary (BTO). Analysis of remaining 201 genes revealed somatic mosaics in and germline mutations in and associating with a high/moderate OC risk significantly; however, further studies are warranted to delineate their contribution to OC development in other populations. Our findings demonstrate the high proportion of patients with hereditary OC in Slavic population justifying genetic testing in all patients with OC, including BTO.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cancers12040956DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7226062PMC
April 2020

Desminopathy: Novel Desmin Variants, a New Cardiac Phenotype, and Further Evidence for Secondary Mitochondrial Dysfunction.

J Clin Med 2020 Mar 29;9(4). Epub 2020 Mar 29.

Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, 11636 Prague, Czech Republic.

The pleomorphic clinical presentation makes the diagnosis of desminopathy difficult. We aimed to describe the prevalence, phenotypic expression, and mitochondrial function of individuals with putative disease-causing desmin (DES) variants identified in patients with an unexplained etiology of cardiomyopathy. A total of 327 Czech patients underwent whole exome sequencing and detailed phenotyping in probands harboring DES variants. Rare, conserved, and possibly pathogenic DES variants were identified in six (1.8%) probands. Two DES variants previously classified as variants of uncertain significance (p.(K43E), p.(S57L)), one novel DES variant (p.(A210D)), and two known pathogenic DES variants (p.(R406W), p.(R454W)) were associated with characteristic desmin-immunoreactive aggregates in myocardial and/or skeletal biopsy samples. The individual with the novel DES variant p.(Q364H) had a decreased myocardial expression of desmin with absent desmin aggregates in myocardial/skeletal muscle biopsy and presented with familial left ventricular non-compaction cardiomyopathy (LVNC), a relatively novel phenotype associated with desminopathy. An assessment of the mitochondrial function in four probands heterozygous for a disease-causing DES variant confirmed a decreased metabolic capacity of mitochondrial respiratory chain complexes in myocardial/skeletal muscle specimens, which was in case of myocardial succinate respiration more profound than in other cardiomyopathies. The presence of desminopathy should also be considered in individuals with LVNC, and in the differential diagnosis of mitochondrial diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/jcm9040937DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7231262PMC
March 2020

Renal transplant outcomes in patients with autosomal dominant tubulointerstitial kidney disease.

Clin Transplant 2020 02 5;34(2):e13783. Epub 2020 Feb 5.

Nephrology Department, Beaumont Hospital, Dublin, Ireland.

Introduction: Autosomal dominant tubulointerstitial kidney disease (ADTKD) is a rare genetic cause of chronic kidney disease (CKD) and end-stage renal disease (ESRD). We aimed to compare renal transplant outcomes in people with ESRD due to ADTKD to those with other causes of renal failure.

Methods: Patients with clinical characteristics consistent with ADTKD by the criteria outlined in the 2015 KDIGO consensus were included. We compared ADTKD transplant outcomes with those of 4633 non-ADTKD renal transplant recipients.

Results: We included 31 patients who met diagnostic criteria for ADTKD in this analysis, 23 of whom had an identified mutation (28 were categorized as definite-ADTKD and 3 as suspected ADTKD). Five patients received a second transplant during follow-up. In total, 36 grafts were included. We did not identify significant differences between groups in terms of graft or patient survival after transplantation. Twenty-five transplant biopsies were performed during follow-up, and none of these showed signs of recurrent ADTKD post-transplant.

Conclusion: In patients with ESRD due to ADTKD, we demonstrate that transplant outcomes are comparable with the general transplant population. There is no evidence that ADTKD can recur after transplantation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/ctr.13783DOI Listing
February 2020

Autosomal-dominant adult neuronal ceroid lipofuscinosis caused by duplication in DNAJC5 initially missed by Sanger and whole-exome sequencing.

Eur J Hum Genet 2020 06 9;28(6):783-789. Epub 2020 Jan 9.

Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic.

Adult-onset neuronal ceroid lipofuscinoses (ANCL, Kufs disease) are rare hereditary neuropsychiatric disorders characterized by intralysosomal accumulation of ceroid in tissues. The ceroid accumulation primarily affects the brain, leading to neuronal loss and progressive neurodegeneration. Although several causative genes have been identified (DNAJC5, CLN6, CTSF, GRN, CLN1, CLN5, ATP13A2), the genetic underpinnings of ANCL in some families remain unknown. Here we report one family with autosomal dominant (AD) Kufs disease caused by a 30 bp in-frame duplication in DNAJC5, encoding the cysteine-string protein alpha (CSPα). This variant leads to a duplication of the central core motif of the cysteine-string domain of CSPα and affects palmitoylation-dependent CSPα sorting in cultured neuronal cells similarly to two previously described CSPα variants, p.(Leu115Arg) and p.(Leu116del). Interestingly, the duplication was not detected initially by standard Sanger sequencing due to a preferential PCR amplification of the shorter wild-type allele and allelic dropout of the mutated DNAJC5 allele. It was also missed by subsequent whole-exome sequencing (WES). Its identification was facilitated by reanalysis of original WES data and modification of the PCR and Sanger sequencing protocols. Independently occurring variants in the genomic sequence of DNAJC5 encoding the cysteine-string domain of CSPα suggest that this region may be more prone to DNA replication errors and that insertions or duplications within this domain should be considered in unsolved ANCL cases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41431-019-0567-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7253421PMC
June 2020

Alu-mediated Xq24 deletion encompassing CUL4B, LAMP2, ATP1B4, TMEM255A, and ZBTB33 genes causes Danon disease in a female patient.

Am J Med Genet A 2020 01 15;182(1):219-223. Epub 2019 Nov 15.

Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, 1st Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic.

Cullin 4B (CUL4B), lysosomal-associated membrane protein Type 2 (LAMP2), ATP1B4, TMEM255A, and ZBTB33 are neighboring genes on Xq24. Mutations in CUL4B result in Cabezas syndrome (CS). Male CS patients present with dysmorphic, neuropsychiatric, genitourinary, and endocrine abnormalities. Heterozygous CS females are clinically asymptomatic. LAMP2 mutations cause Danon disease (DD). Cardiomyopathy is a dominant feature of DD present in both males and heterozygous females. No monogenic phenotypes have been associated with mutations in ATP1B4, TMEM255A, and ZBTB33 genes. To facilitate diagnostics and counseling in CS and DD families, we present a female DD patient with a de novo Alu-mediated Xq24 rearrangement causing a deletion encompassing CUL4B, LAMP2, and also the other three neighboring genes. Typical to females heterozygous for CUL4B mutations, the patient was CS asymptomatic, however, presented with extremely skewed X-chromosome inactivation (XCI) ratios in peripheral white blood cells. As a result of the likely selection against CUL4B deficient clones, only minimal populations (~3%) of LAMP2 deficient leukocytes were identified by flow cytometry. On the contrary, myocardial LAMP2 protein expression suggested random XCI. We demonstrate that contiguous CUL4B and LAMP2 loss-of-function copy number variations occur and speculate that male patients carrying similar defects could present with features of both CS and DD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ajmg.a.61416DOI Listing
January 2020

PAICS deficiency, a new defect of de novo purine synthesis resulting in multiple congenital anomalies and fatal outcome.

Hum Mol Genet 2019 11;28(22):3805-3814

Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital, 12808 Prague, Czech Republic.

We report for the first time an autosomal recessive inborn error of de novo purine synthesis (DNPS)-PAICS deficiency. We investigated two siblings from the Faroe Islands born with multiple malformations resulting in early neonatal death. Genetic analysis of affected individuals revealed a homozygous missense mutation in PAICS (c.158A>G; p.Lys53Arg) that affects the structure of the catalytic site of the bifunctional enzyme phosphoribosylaminoimidazole carboxylase (AIRC, EC 4.1.1.21)/phosphoribosylaminoimidazole succinocarboxamide synthetase (SAICARS, EC 6.3.2.6) (PAICS). The mutation reduced the catalytic activity of PAICS in heterozygous carrier and patient skin fibroblasts to approximately 50 and 10% of control levels, respectively. The catalytic activity of the corresponding recombinant enzyme protein carrying the mutation p.Lys53Arg expressed and purified from E. coli was reduced to approximately 25% of the wild-type enzyme. Similar to other two known DNPS defects-adenylosuccinate lyase deficiency and AICA-ribosiduria-the PAICS mutation prevented purinosome formation in the patient's skin fibroblasts, and this phenotype was corrected by transfection with the wild-type but not the mutated PAICS. Although aminoimidazole ribotide (AIR) and aminoimidazole riboside (AIr), the enzyme substrates that are predicted to accumulate in PAICS deficiency, were not detected in patient's fibroblasts, the cytotoxic effect of AIr on various cell lines was demonstrated. PAICS deficiency is a newly described disease that enhances our understanding of the DNPS pathway and should be considered in the diagnosis of families with recurrent spontaneous abortion or early neonatal death.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/hmg/ddz237DOI Listing
November 2019

Quality of life in patients with autosomal dominant tubulointerstitial kidney disease
.

Clin Nephrol 2019 Dec;92(6):302-311

Aims: The reaction to diagnosis and quality of life (QOL) in autosomal dominant tubulointerstitial kidney disease (ADTKD) due to UMOD and MUC mutations from the time of diagnosis until treatment for end-stage kidney disease (ESKD) has not been characterized. It is unclear how asymptomatic patients react to a positive genetic test result.

Materials And Methods: A cross-sectional survey concerning QOL and genetic testing was delivered to 622 individuals who had undergone genetic testing from families with known ADTKD.

Results: 286 of 622 individuals completed the survey, including 61 (21%) genetically unaffected, 36 (12%) with stage 1, 2 chronic kidney disease (CKD), 51 (18%) stage 3, 41 (14%) stage 4 pre-dialysis, 50 (17%) receiving dialysis, and 47 (16%) s/p kidney transplantation. Of 55 respondents who thought they had normal kidney function at the time of testing and were found to have ADTKD, 51 (93%) were happy testing was performed, 3 (5%) neutral, and 1 (2%) neutral/unhappy. 42 of 183 (23%) affected individuals stated that ADTKD "has a substantial effect and I think about it daily," 47 (26%) think about ADTKD weekly, 48 (26%) monthly, and 48 (26%) less than monthly. The mean PROMIS anxiety score was similar between unaffected and affected individuals and the general population. Depression was present in 41% of affected vs. 23% of unaffected individuals (p = 0.01).

Conclusion: Genetic testing of presymptomatic patients for ADTKD is reasonable when requested. This study provides reassurance regarding the impact on QOL of the increased use of genetic testing to diagnose kidney disease. ADTKD has a significant impact on QOL, with depression, not anxiety, being more prevalent in affected individuals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5414/CN109842DOI Listing
December 2019

POLR3B-associated leukodystrophy: clinical, neuroimaging and molecular-genetic analyses in four patients: clinical heterogeneity and novel mutations in POLR3B gene.

Neurol Neurochir Pol 2019 2;53(5):369-376. Epub 2019 Oct 2.

Clinic of Pediatric and Adolescent Medicine, 1st Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 12109 Prague, Czech Republic.

Introduction And Aim Of The Study: White matter disorders represent a spectrum of neurological diseases frequently associated with an unfavourable prognosis and a delay in diagnostics. We report the broad phenotypic spectrum of a rare hypomyelinating leukodystrophy and three novel mutations. Further, we aim to explore the role of the combined clinical and neuroimaging diagnostic approach in the era of whole exome sequencing.

Materials And Methods: We present a clinical, neuroimaging and molecular-genetic characterisation of four patients from three families suffering from a rare genetic leukoencephalopathy. Two severely affected siblings (P1, P2) manifested a profound developmental delay, cerebellar symptomatology, microcephaly, failure to thrive, short stature and delayed teeth eruption with oligodontia. The other two patients (P3, P4), on the contrary, suffer from substantially less serious impairment with mild to moderate developmental delay and cerebellar symptomatology, delayed teeth eruption, or well-manageable epilepsy. In all four patients, magnetic resonance revealed cerebellar atrophy and supratentorial hypomyelination with T2-weight hypointensities in the areas of the ventrolateral thalamic nuclei, corticospinal tract and the dentate nuclei.

Results: Using whole-exome sequencing in P1, P2 and P3, and targeted sequencing in P4, pathogenic variants were disclosed in POLR3B, a gene encoding one of 17 subunits of DNA-dependent RNA polymerase III - all patients were compound heterozygotes for point mutations. Three novel mutations c.727A>G (p.Met243Val) and c.2669G>A (p.Arg890His) (P1, P2), and c.1495G>A (p.Met499Val) (P3) were found. Magnetic resonance revealed the characteristic radiological pattern of POLR3-leukodystrophies in our patients.

Conclusion And Clinical Implications: The diagnosis of POLR3-associated leukodystrophies can be significantly accelerated using the combined clinical and neuroradiological recognition pattern. Therefore, it is of crucial importance to raise the awareness of this rare disorder among clinicians. Molecular-genetic analyses are indispensable for a swift diagnosis confirmation in cases of clear clinical suspicion, and for diagnostic search in patients with less pronounced symptomatology. They represent an invaluable tool for unravelling the complex genetic background of heritable white matter disorders.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5603/PJNNS.a2019.0042DOI Listing
November 2019

Autosomal dominant tubulointerstitial kidney disease.

Nat Rev Dis Primers 2019 09 5;5(1):60. Epub 2019 Sep 5.

Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, NC, USA.

Autosomal dominant tubulointerstitial kidney disease (ADTKD) is a recently defined entity that includes rare kidney diseases characterized by tubular damage and interstitial fibrosis in the absence of glomerular lesions, with inescapable progression to end-stage renal disease. These diseases have long been neglected and under-recognized, in part due to confusing and inconsistent terminology. The introduction of a gene-based, unifying terminology led to the identification of an increasing number of cases, with recent data suggesting that ADTKD is one of the more common monogenic kidney diseases after autosomal dominant polycystic kidney disease, accounting for ~5% of monogenic disorders causing chronic kidney disease. ADTKD is caused by mutations in at least five different genes, including UMOD, MUC1, REN, HNF1B and, more rarely, SEC61A1. These genes encode various proteins with renal and extra-renal functions. The mundane clinical characteristics and lack of appreciation of family history often result in a failure to diagnose ADTKD. This Primer highlights the different types of ADTKD and discusses the distinct genetic and clinical features as well as the underlying mechanisms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41572-019-0109-9DOI Listing
September 2019

Germline CHEK2 Gene Mutations in Hereditary Breast Cancer Predisposition - Mutation Types and their Biological and Clinical Relevance.

Klin Onkol 2019 ;32(Supplementum2):36-50

Background: Hereditary mutations in the CHEK2 gene (which encodes CHK2 kinase) contribute to a moderately increased risk of breast cancer (BC) and other cancers. Large variations in the frequency of CHEK2 mutations and the occurrence of variants of unknown clinical significance (VUS) complicate estimation of cancer risk in carriers of germline CHEK2 mutations.

Patients And Methods: We performed mutation analysis of 1,526 high-risk Czech BC patients and 3,360 Czech controls. Functional analysis was performed for identified VUS using a model system based on a human RPE1-CHEK2-KO cell line harboring biallelic inactivation of endogenous CHEK2.

Results: The frequency of ten truncating CHEK2 variants differed markedly between BC patients (2.26%) and controls (0.11%; p = 4.1 × 1012). We also found 23 different missense variants in 4.5% patients and in 4.0% of controls. The most common was p.I157T, which was found in patients and controls with the same frequency. Functional analysis identified nine functionally deleterious VUS, another nine functionally neutral VUS, and four intermediate VUS (including p.I157T). We found that carriers of truncating CHEK2 mutations had a high BC risk (OR 8.19; 95% CI 4.11-17.75), and that carriers of functionally deleterious missense variants had a moderate risk (OR 4.06; 95% CI, 1.37-13.39). Carriers of these mutations developed BC at 44.4 and 50.7 years, respectively. Functionally neutral and functionally intermediate missense variants did not increase the BC risk. BC in CHEK2 mutation carriers was frequently ER-positive and of higher grade. Notably, carriers of CHEK2 mutations developed second cancers more frequently than BRCA1/BRCA2/PALB2/p53 or mutation non-carriers.

Conclusion: Hereditary CHEK2 mutations contribute to the development of hereditary BC. The associated cancer risk in mutation carriers increases with the number of affected individuals in a family. Annual follow-up with breast ultrasound, mammography, or magnetic resonance imaging is recommended for asymptomatic mutation carriers from the age of 40. Surgical prevention and specific follow-up of other tumors should be considered based on family cancer history. The work was supported by grants from the Czech Health Research Council of the Ministry of Health of the Czech Republic NR 15-28830A, 16-29959A, NV19-03-00279, projects of the PROGRES Q28/LF1, GAUK 762216, SVV2019 / 260367, PRIMUS/17/MED/9, UNCE/MED/016, Progress Q26, LQ1604 NPU II and project AVČR Qualitas. The analysis of a set of unselected controls was made possible by the existence and support of the scientific infrastructure of the National Center for Medical Genomics (LM2015091) and its project aimed at creating a reference database of genetic variants of the Czech Republic (CZ.02.1.01/0.0/0.0/16_013/0001634). The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 2. 4. 2019 Accepted: 14. 5. 2019.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.14735/amko2019S36DOI Listing
January 2020

Small Molecule Targets TMED9 and Promotes Lysosomal Degradation to Reverse Proteinopathy.

Cell 2019 07;178(3):521-535.e23

Broad Institute of MIT and Harvard, Cambridge, MA, USA; Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA. Electronic address:

Intracellular accumulation of misfolded proteins causes toxic proteinopathies, diseases without targeted therapies. Mucin 1 kidney disease (MKD) results from a frameshift mutation in the MUC1 gene (MUC1-fs). Here, we show that MKD is a toxic proteinopathy. Intracellular MUC1-fs accumulation activated the ATF6 unfolded protein response (UPR) branch. We identified BRD4780, a small molecule that clears MUC1-fs from patient cells, from kidneys of knockin mice and from patient kidney organoids. MUC1-fs is trapped in TMED9 cargo receptor-containing vesicles of the early secretory pathway. BRD4780 binds TMED9, releases MUC1-fs, and re-routes it for lysosomal degradation, an effect phenocopied by TMED9 deletion. Our findings reveal BRD4780 as a promising lead for the treatment of MKD and other toxic proteinopathies. Generally, we elucidate a novel mechanism for the entrapment of misfolded proteins by cargo receptors and a strategy for their release and anterograde trafficking to the lysosome.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cell.2019.07.002DOI Listing
July 2019

Outcomes of patient self-referral for the diagnosis of several rare inherited kidney diseases.

Genet Med 2020 01 24;22(1):142-149. Epub 2019 Jul 24.

Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, NC, USA.

Purpose: To evaluate self-referral from the Internet for genetic diagnosis of several rare inherited kidney diseases.

Methods: Retrospective study from 1996 to 2017 analyzing data from an academic referral center specializing in autosomal dominant tubulointerstitial kidney disease (ADTKD). Individuals were referred by academic health-care providers (HCPs) nonacademic HCPs, or directly by patients/families.

Results: Over 21 years, there were 665 referrals, with 176 (27%) directly from families, 269 (40%) from academic HCPs, and 220 (33%) from nonacademic HCPs. Forty-two (24%) direct family referrals had positive genetic testing versus 73 (27%) families from academic HCPs and 55 (25%) from nonacademic HCPs (P = 0.72). Ninety-nine percent of direct family contacts were white and resided in zip code locations with a mean median income of $77,316 ± 34,014 versus US median income $49,445.

Conclusion: Undiagnosed families with Internet access bypassed their physicians and established direct contact with an academic center specializing in inherited kidney disease to achieve a diagnosis. Twenty-five percent of all families diagnosed with ADTKD were the result of direct family referral and would otherwise have been undiagnosed. If patients suspect a rare disorder that is undiagnosed by their physicians, actively pursuing self-diagnosis using the Internet can be successful. Centers interested in rare disorders should consider improving direct access to families.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-019-0617-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6946861PMC
January 2020

Diagnostic Utility of Exome Sequencing for Kidney Disease.

N Engl J Med 2019 05;380(21):2080

Broad Institute of MIT and Harvard, Boston, MA.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1056/NEJMc1903250DOI Listing
May 2019

Identification of deleterious germline CHEK2 mutations and their association with breast and ovarian cancer.

Int J Cancer 2019 10 20;145(7):1782-1797. Epub 2019 May 20.

Institute of Biochemistry and Experimental Oncology, First Faculty of Medicine, Charles University, Prague, Czech Republic.

Germline mutations in checkpoint kinase 2 (CHEK2), a multiple cancer-predisposing gene, increase breast cancer (BC) risk; however, risk estimates differ substantially in published studies. We analyzed germline CHEK2 variants in 1,928 high-risk Czech breast/ovarian cancer (BC/OC) patients and 3,360 population-matched controls (PMCs). For a functional classification of VUS, we developed a complementation assay in human nontransformed RPE1-CHEK2-knockout cells quantifying CHK2-specific phosphorylation of endogenous protein KAP1. We identified 10 truncations in 46 (2.39%) patients and in 11 (0.33%) PMC (p = 1.1 × 10 ). Two types of large intragenic rearrangements (LGR) were found in 20/46 mutation carriers. Truncations significantly increased unilateral BC risk (OR = 7.94; 95%CI 3.90-17.47; p = 1.1 × 10 ) and were more frequent in patients with bilateral BC (4/149; 2.68%; p = 0.003), double primary BC/OC (3/79; 3.80%; p = 0.004), male BC (3/48; 6.25%; p = 8.6 × 10 ), but not with OC (3/354; 0.85%; p = 0.14). Additionally, we found 26 missense VUS in 88 (4.56%) patients and 131 (3.90%) PMC (p = 0.22). Using our functional assay, 11 variants identified in 15 (0.78%) patients and 6 (0.18%) PMC were scored deleterious (p = 0.002). Frequencies of functionally intermediate and neutral variants did not differ between patients and PMC. Functionally deleterious CHEK2 missense variants significantly increased BC risk (OR = 3.90; 95%CI 1.24-13.35; p = 0.009) and marginally OC risk (OR = 4.77; 95%CI 0.77-22.47; p = 0.047); however, carriers low frequency will require evaluation in larger studies. Our study highlights importance of LGR detection for CHEK2 analysis, careful consideration of ethnicity in both cases and controls for risk estimates, and demonstrates promising potential of newly developed human nontransformed cell line assay for functional CHEK2 VUS classification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ijc.32385DOI Listing
October 2019

Modern methods in diagnostics and research of molecular bases of rare diseases.

Cas Lek Cesk Summer 2018;157(3):133-136

Rare diseases represent a heterogeneous group of approximately 8000 various disorders and affect nearly 8 % of the population. The local and international studies of human genomes help to increase the knowledge about genetic variability of the man and due to effective sharing of clinical and molecular data in the registries enable casual diagnostics of the broad spectrum of rare and complex diseases in 55-65 % of the cases. With the diagnostics in the remaining group of patients, new methods and technologies studying human genome are of importance including genetic and functional analyses of genomic variants and their combinations with the aims to recognize and interpret the significances of the somatic mosaics, genetic heterogeneity of individual disorders, the presence of eventual phenocopy, different penetrance and expressivity of individual mutation and diseases with the oligogenic inheritance. Recently, the increasing significance of analyses of noncoding regions in human DNA were recognized including the impact of repetitive and homologs regions on transcription and structure of mRNA. For the diagnostics of genetic causality in patients is necessary to focus on analyses of biologic fluids, tissues, cultivated cells and animal models prepared by methods of cell reprogramming or directed mutagenesis. In this paper, the overview of methods and their importance and limitation is described including whole exome sequencing (WES), whole genome sequencing, functional and homolog cloning, functional complementation, mapping of genes with the help of binding analyses and matching of the results from individual genome with genetic variability in the adequate population. In our institutions, we performed WES in > 520 patients with successful diagnostics above 50 %. In addition, in our group of 225 patients with rare diseases we compared the result of WES with the results of direct sequencing of individual genes indicated by clinical geneticist from various regions of the country and we recognized much higher diagnostic and economic value of WES. Modern diagnostics of rare diseases is time and money consuming and requires close cooperation between patients, their families, attending physicians, clinical geneticists and experts from various laboratories involved in biologic oriented research. It represents a big challenge for organisers and payers of the health care system. Keywords: are diseases, complex disorders, whole exome sequencing, gene mapping.
View Article and Find Full Text PDF

Download full-text PDF

Source
April 2019

Clinical manifestations and molecular aspects of phosphoribosylpyrophosphate synthetase superactivity in females.

Rheumatology (Oxford) 2018 07;57(7):1180-1185

Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University, Prague, Czech Republic.

Objectives: Phosphoribosylpyrophosphate synthetase (PRPS1) superactivity is an X-linked disorder characterized by urate overproduction Online Mendelian Inheritance in Man (OMIM) gene reference 300661. This condition is thought to rarely affect women, and when it does, the clinical presentation is mild. We describe a 16-year-old African American female who developed progressive tophi, nephrolithiasis and acute kidney failure due to urate overproduction. Family history included a mother with tophaceous gout who developed end-stage kidney disease due to nephrolithiasis and an affected sister with polyarticular gout. The main aim of this study was to describe the clinical manifestations of PRPS1 superactivity in women.

Methods: Whole exome sequencing was performed in affected females and their fathers.

Results: Mutational analysis revealed a new c.520 G > A (p.G174R) mutation in the PRPS1 gene. The mutation resulted in decreased PRPS1 inhibition by ADP.

Conclusion: Clinical findings in previously reported females with PRPS1 superactivity showed a high clinical penetrance of this disorder with a mean serum urate level of 8.5 (4.1) mg/dl [506 (247) μmol/l] and a high prevalence of gout. These findings indicate that all women in families with PRPS1 superactivity should be genetically screened for a mutation (for clinical management and genetic counselling). In addition, women with tophaceous gout, gout presenting in childhood, or a strong family history of severe gout should be considered for PRPS1 mutational analysis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/rheumatology/key041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6232955PMC
July 2018

Rare copy number variation in extremely impulsively violent males.

Genes Brain Behav 2019 07 3;18(6):e12536. Epub 2018 Dec 3.

Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic.

The genetic correlates of extreme impulsive violence are poorly understood, and there have been no studies that have systematically characterized a large group of affected individuals both clinically and genetically. We performed a genome-wide rare copy number variant (CNV) analysis in 281 males from four Czech prisons who met strict clinical criteria for extreme impulsive violence. Inclusion criteria included age ≥ 18 years, an ICD-10 diagnosis of Dissocial Personality Disorder, and the absence of an organic brain disorder. Participants underwent a structured psychiatric assessment to diagnose extreme impulsive violence and then provided a blood sample for genetic analysis. DNA was genotyped and CNVs were identified using Illumina HumanOmni2.5 single-nucleotide polymorphism array platform. Comparing with 10851 external population controls, we identified 828 rare CNVs (frequency ≤ 0.1% among control samples) in 264 participants. The CNVs impacted 754 genes, with 124 genes impacted more than once (2-25 times). Many of these genes are associated with autosomal dominant or X-linked disorders affecting adult behavior, cognition, learning, intelligence, specifically expressed in the brain and relevant to synapses, neurodevelopment, neurodegeneration, obesity and neuropsychiatric phenotypes. Specifically, we identified 31 CNVs of clinical relevance in 31 individuals, 59 likely clinically relevant CNVs in 49 individuals, and 17 recurrent CNVs in 65 individuals. Thus, 123 of 281 (44%) individuals had one to several rare CNVs that were indirectly or directly relevant to impulsive violence. Extreme impulsive violence is genetically heterogeneous and genomic analysis is likely required to identify, further research and specifically treat the causes in affected individuals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/gbb.12536DOI Listing
July 2019