Publications by authors named "Erwin Petek"

38 Publications

Cardio-pathogenic variants in unexplained intrauterine fetal death: a retrospective pilot study.

Sci Rep 2021 Mar 24;11(1):6737. Epub 2021 Mar 24.

Institute of Human Genetics, Medical University of Graz, Graz, Austria.

To describe the prevalence and spectrum of cardio-pathogenic variants in singleton fetuses after unexplained intrauterine fetal death (IUFD). DNA from post-mortem fibroblastic tissue samples of 16 fetuses after unexplained IUFD was retrieved at two tertiary university hospitals for clinical exome sequencing with subsequent filtering of 122 cardio-specific genes to elucidate underlying cardio-pathogenic variants. In total, we included 12 (75%) male and four (25%) female fetuses who were stillborn at a median gestational age of 34 (23-40) weeks. In two (12.5%) fetuses no cardio-pathogenic variants were found. In 14 (87.5%) fetuses, overall 33 variants were detected in 22 cardio-specific genes, involving 14 (63.63%) genes associated with cardiomyopathy, six (27.27%) arrhythmogenic susceptibility genes and two (9.09%) arrhythmia and cardiomyopathy associated genes. Among the 33 variants, five (15.2%) were classified as likely benign according to the American College of Medical Genetics and Genomics; 28 (84.8%) variants were considered as variants of uncertain significance. Compared to a cohort of explained IUFDs, the cases with and without fetal variants in cardiac genes differed not significantly regarding maternal age, previous history of stillbirth, time of stillbirth or fetal sex. Unexplained stillbirth may be caused by cardio-genetic pathologies, yet a high number of variants of uncertain significance merit a more detailed post-mortem examination including family segregation analysis.
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http://dx.doi.org/10.1038/s41598-021-85893-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7991630PMC
March 2021

Identification of a novel protein truncating mutation p.Asp98* in XPC associated with xeroderma pigmentosum in a consanguineous Pakistani family.

Mol Genet Genomic Med 2020 02 10;8(2):e1060. Epub 2020 Jan 10.

Diagnostic & Research Institute of Human Genetics, Medical University of Graz, Graz, Austria.

Background: Xeroderma pigmentosum (XP) is a rare genetic disorder, which is characterized by hyper-sensitivity to solar ultraviolet (UV) radiation. Clinical consequences of sun exposure are skin lesions and an increased risk of developing skin cancer. Genetic studies have identified eight genes associated with xeroderma pigmentosum. The proteins encoded by these genes are mainly involved in DNA repair mechanisms.

Methods: Molecular genetic characterization of patients with xeroderma pigmentosum involved positional cloning methods such as homozygosity mapping and subsequent candidate gene analysis. Mutation screening was performed through Sanger DNA sequencing.

Results And Discussion: In this case study, we report a novel protein truncating mutation in XPC associated with autosomal recessive xeroderma pigmentosum in a consanguineous Pakistani family. Genetic mapping revealed a novel single base insertion of a thymine nucleotide NM_004628.4: c.291dupT (c.291_292insT) in the second exon of XPC. The identified mutation leads to a premature stop codon (TGA) at amino acid position 98 (p.Asp98*) and thus presumably results in a truncated protein. The Xeroderma pigmentosum, complementation group C (XPC) is located on 3p25.1 and encodes a protein involved in nucleotide excision repair. The identified mutation presumably truncates all functional domains of the XPC protein, which likely results in the loss of protein function.

Conclusion: The study expands the knowledge of the mutational spectrum of XPC and is valuable for genetic counseling of affected individuals and their families.
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http://dx.doi.org/10.1002/mgg3.1060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7005610PMC
February 2020

Genetic study of Khyber-Pukhtunkhwa resident Pakistani families presenting primary microcephaly with intellectual disability.

J Pak Med Assoc 2019 Dec;69(12):1812-1816

Gomal Centre of Biochemistry and Biotechnology, Gomal University, D.I. Khan, Khyber Pakhtunkhwa, Pakistan.

Objective: To investigate the genetic factor responsible for causing microcephaly and determine allelic heterogeneity of Abnormal spindle microtubule gene.

Methods: The genetic study was conducted at the Kohat University of Science and Technology, Kohat, and Gomal University, D.I.Khan, Pakistan, during 2017-18, and comprised 5 consanguineous families from South Waziristan, Kurram Agency, Karak, Bannu and Dera Ismail Khan regions of the country's Khyber Pakhtukhwa province. Blood samples from all available and cooperative family members (including normal and affected) were obtained, and molecular analysis was carried out through whole genome single nucleotide polymorphisms genotyping, exome sequencing and Sanger sequencing.

Results: Of the 15 patients, 9(60%) were males and 6(40%) were females. Genetic mapping revealed linkage to the MCPH5 locus which harbours the microcephaly-associated abnormal spindle-like microcephaly gene. Mutation analysis of the gene identified missense mutation c.3978G>A (p.Trp1326*) in families A, B and C, a deletion mutation c.7782_7783delGA (p.(Lys2595Serfs*6)) in family D, and a splice site defect c.2936+5G>A in family E.

Conclusions: There was suggestion of strong founder effect of mutation c.3978G>A (p.Trp1326*).
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http://dx.doi.org/10.5455/JPMA.300681DOI Listing
December 2019

Prenatal Detection of Chromosome Aneuploidy by Quantitative Fluorescence PCR.

Methods Mol Biol 2019 ;1885:139-160

Prenatal Centre, Ragnitz Hospital, Graz, Austria.

Autosomal chromosome aneuploid pregnancies that survive to term, namely, trisomies 13, 18, and 21, account for 89% of chromosome abnormalities with a severe phenotype identified in prenatal samples. They are traditionally detected by full karyotype analysis of cultured cells. The average reporting time for a prenatal karyotype analysis is approximately 14 days, and in recent years, there has been increasing demand for more rapid prenatal results with respect to the common chromosome aneuploidies, to relieve maternal anxiety and facilitate options in pregnancy. The rapid tests that have been developed negate the requirement for cultured cells, instead directly testing cells from the amniotic fluid or chorionic villus sample, with the aim of generating results within 48 h of sample receipt. Interphase fluorescence in situ hybridization is the method of choice in some genetic laboratories, usually because the expertise and equipment are readily available. However, a quantitative fluorescence (QF)-PCR-based approach is now widely used and reported as a clinical diagnostic service in many studies. It may be used as a stand-alone test or as an adjunct test to full karyotype or array CGH analysis, which scan for other chromosome abnormalities not detected by the QF-PCR assay.
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http://dx.doi.org/10.1007/978-1-4939-8889-1_10DOI Listing
June 2019

Time-lapse imaging provides further evidence that planar arrangement of blastomeres is highly abnormal.

Arch Gynecol Obstet 2017 Dec 20;296(6):1199-1205. Epub 2017 Sep 20.

Department of Gynecology, Obstetrics and Gynecological Endocrinology, Kepler University Clinic, Campus IV, Krankenhausstr. 26-30, 4020, Linz, Upper Austria, Austria.

Purpose: Recently, guidelines on the annotation of dynamic human embryo monitoring recommended screening for the presence of planar blastomere arrangement at the 4-cell stage. This observational study was set up in order to analyze whether developmental kinetics of planar human embryos are different from tetrahedral ones.

Methods: Therefore, embryos of 115 consecutive ICSI patients (showing 32 planar and 554 tetrahedral embryos) were cultured in a new time-lapse system (Miri TL) and their embryos were annotated for morphokinetic development and screened for irregular cleavages and morphological dysmorphisms.

Results: Significantly less planar embryos reached blastocyst stage and showed worse quality as compared to regular tetrahedral embryos. The rate of bi- and/or multinucleation was also significantly higher in the affected group. Irregular cleavages, particularly embryo rolling, were more often seen in planar embryos. Morphokinetics between planar and tetrahedral were distinguishable up to 4-cell stage (t2-t4), thereafter the observed delay in planar embryos (t8) was more likely the result of a higher rate of arrested embryos in the planar group.

Conclusions: Planar embryos are associated with both a significant increase in irregular cleavage as well as a delay in preimplantation development. This indicates that planar embryos are rather abnormal and should only be considered for transfer if no other embryos are available.
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http://dx.doi.org/10.1007/s00404-017-4531-5DOI Listing
December 2017

Is the molecular clock ticking differently in bipolar disorder? Methylation analysis of the clock gene ARNTL.

World J Biol Psychiatry 2018 14;19(sup2):S21-S29. Epub 2016 Oct 14.

h Institute of Neuropathology , University of Bonn , Germany.

Objectives: The clock gene ARNTL is associated with the transcription activation of monoamine oxidase A according to previous literature. Thus, we hypothesised that methylation of ARNTL may differ between bipolar disorder (BD) and controls.

Methods: The methylation status of one CpG island covering the first exon of ARNTL (PS2) and one site in the 5' region of ARNTL (cg05733463) were analysed in patients with BD (n = 151) versus controls (n = 66). Methylation analysis was performed by bisulphite-conversion of DNA from fasting blood with the EpiTect Bisulfite Kit, PCR and pyrosequencing. Analysis of covariances considering the covariates age, body mass index, sex, smoking, lithium and anticonvulsant intake were performed to test methylation differences between BD and controls.

Results: Methylation at cg05733463 of ARNTL was significantly higher in BD than in controls (F(1,209) = 44.500, P < .001). In contrast, methylation was significantly lower in BD at PS2_POS1 compared to controls (F(1,128) = 5.787, P = .018) and by trend at PS2_POS2 (F(1,128) = 3.033, P = .084) and POS7 (F(1,34) = 3.425, P = .073).

Conclusions: Methylation of ARNTL differed significantly between BD and controls. Thus, our study suggests that altered epigenetic regulation of ARNTL might provide a mechanistic basis for better understanding circadian rhythms and mood swings in BD.
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http://dx.doi.org/10.1080/15622975.2016.1231421DOI Listing
June 2019

Characterization of the injection funnel during intracytoplasmic sperm injection reflects cytoplasmic maturity of the oocyte.

Fertil Steril 2016 Oct 20;106(5):1101-1106. Epub 2016 Jun 20.

Department of Gynecology, Obstetrics, and Gynecologic Endocrinology, Kepler University Hospital, Linz, Austria. Electronic address:

Objective: To quantify cytoplasmic maturity on the basis of intracytoplasmic sperm injection (ICSI) injection funnel manifestation and to evaluate influence factors of the latter.

Design: Prospective study.

Setting: Private fertility center.

Patient(s): A total of 31 patients with good ovarian response.

Intervention(s): Mature and immature oocytes were injected intracytoplasmatically. Formation and persistence of an injection funnel was documented and measured.

Main Outcome Measure(s): ICSI funnel size, persistence of injection funnel, rates of degeneration and fertilization, embryo quality.

Result(s): Funnel volume in germinal vesicle stage oocytes (prophase I [PI]) was significantly smaller than that of metaphase I (MI) and MII oocytes. Immature eggs (PI, MI) almost never showed a persistent funnel 2-4 minutes after ICSI, whereas in MII eggs the funnel was still observable in 35% (117/334) of the cases. Uni- and multivariate analysis revealed that pipette type and stimulation protocol significantly influenced appearance of injection funnel. Funnel volume in oocytes that fertilized regularly was significantly higher compared with three-polar body and degenerated oocytes.

Conclusion(s): Oocyte maturation within the follicle is closely associated with a remarkable change in cytoplasm viscosity from an aqueous to a more viscous subtype. Precise evaluation of the injection funnel may help to explain deviations from expected ICSI outcome and could also assist in optimizing controlled ovarian hyperstimulation.
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http://dx.doi.org/10.1016/j.fertnstert.2016.06.015DOI Listing
October 2016

Oocyte competence in in vitro fertilization and intracytoplasmic sperm injection patients suffering from endometriosis and its possible association with subsequent treatment outcome: a matched case-control study.

Acta Obstet Gynecol Scand 2017 Jun 22;96(6):736-744. Epub 2016 Jul 22.

Department of Gynecology, Obstetrics, and Gynecological Endocrinology, Johannes Kepler University, Linz, Austria.

Introduction: Endometriosis affects up to 15% of women of reproductive age. There is an obvious lack of studies dealing with morphological parameters of oocyte morphology in endometriosis patients in assisted reproduction. One aim of the study is to describe oocyte morphology in patients undergoing intracytoplasmic sperm injection suffering from endometriosis. In addition, the impact of endometriosis on in vitro fertilization results is analyzed. Both in vitro fertilization and intracytoplasmic sperm injection patients are then matched with an endometriosis-free control group for highlighting the possible association of endometriosis with pregnancy outcome.

Material And Methods: Oocyte morphology of endometriosis patients was assessed in two groups. Both study group and control group consisted of 129 in vitro fertilization/intracytoplasmic sperm injection cycles each. Patients were matched according to anti-Müllerian hormone, female age, previous treatment cycles, and method of fertilization. Endometriosis was graded according to the revised American Society for Reproductive Medicine guidelines of 1997.

Results: Patients with endometriosis had a significantly lower rate of mature oocytes (p < 0.03) and morphologically normal oocytes (p < 0.001). In particular, brownish oocytes (p < 0.009; stage I-IV) and the presence of refractile bodies (p < 0.001; stage IV) were found to be increased. Endometriosis stage IV was associated with significantly worse-quality oocytes than stages I-III (p < 0.01). Fertilization was significantly reduced in conventional in vitro fertilization but not in intracytoplasmic sperm injection (p < 0.03). This was due to lower fertilization rates in stage III-IV endometriosis compared with stage I-II (p < 0.04). No difference was observed with respect to rates of implantation, clinical pregnancy, miscarriage, live birth, and malformation.

Conclusions: Endometriosis patients, in particular those with severe endometriosis, present lower-quality oocytes. Once fertilized, no impairment of further preimplantation embryo development and pregnancy outcome right up to healthy live birth rate has to be expected.
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http://dx.doi.org/10.1111/aogs.12941DOI Listing
June 2017

Quantitative and qualitative trophectoderm grading allows for prediction of live birth and gender.

J Assist Reprod Genet 2016 Jan 14;33(1):49-57. Epub 2015 Nov 14.

Department of Gynecological Endocrinology and Kinderwunsch Zentrum, Landes- Frauen- und Kinderklinik, Krankenhausstr. 26-30, 4020, Linz, Upper Austria, Austria.

Purpose: Prolonged in vitro culture is thought to affect pre- and postnatal development of the embryo. This prospective study was set up to determine whether quality/size of inner cell mass (ICM) (from which the fetus ultimately develops) and trophectoderm (TE) (from which the placenta ultimately develops) is reflected in birth and placental weight, healthy live-birth rate, and gender after fresh and frozen single blastocyst transfer.

Methods: In 225 patients, qualitative scoring of blastocysts was done according to the criteria expansion, ICM, and TE appearance. In parallel, all three parameters were quantified semi-automatically.

Results: TE quality and cell number were the only parameters that predicted treatment outcome. In detail, pregnancies that continued on to a live birth could be distinguished from those pregnancies that aborted on the basis of TE grade and cell number. Male blastocysts had a 2.53 higher chance of showing TE of quality A compared to female ones. There was no correlation between the appearance of both cell lineages and birth or placental weight, respectively.

Conclusions: The presented correlation of TE with outcome indicates that TE scoring could replace ICM scoring in terms of priority. This would automatically require a rethinking process in terms of blastocyst selection and cryopreservation strategy.
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http://dx.doi.org/10.1007/s10815-015-0609-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4717145PMC
January 2016

Yellow laser acupuncture - A new option for prevention and early intervention of lifestyle-related diseases: A randomized, placebo-controlled trial in volunteers.

Laser Ther 2015 Mar;24(1):53-61

Institute of Human Genetics, Medical University of Graz, Graz, Austria.

Background And Aims: The yellow laser constitutes a totally new option in the field of laser acupuncture, in addition to the already existing red, near infrared, green and violet lasers. Especially for so called lifestyle-related diseases, this could open up new methods of integrative therapy. The goal of the present study was to investigate among other parameters blood pressure (BP), heart rate (HR), heart rate variability (HRV), and temperature effects before, during, and after stimulation of different acupoints with yellow laser.

Subjects And Methods: We recruited 26 healthy volunteers (13 female, 13 male; mean age ± SD 24.1 ± 3.3 years) at the Medical University of Graz. The acupoints Baihui, Neiguan, Taichong and a placebo point were stimulated with a 589 nm (50 mW, 500 µm; 5 min) yellow laser. Blood pressure was measured noninvasively at the wrist; for the registration of the electrocardiogram a medilog AR12 HRV system was used. Effects on temperature were measured with a Flir i7 infrared camera.

Results: There were significant decreases after yellow laser acupuncture in the systolic BP, diastolic BP also decreased (n.s.). HRV in both (men and women) increased. The temperature during the yellow laser stimulation decreased significantly in all measured points. After the stimulation it increased again significantly. Based on a questionnaire volunteers reported a significantly decreased level of stress after yellow laser stimulation.

Conclusion: Significant positive effects on BP and well-being were found after yellow laser stimulation. The results are very promising and can be very important especially for the treatment of lifestyle related diseases.
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http://dx.doi.org/10.5978/islsm.15-OR-07DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4416147PMC
March 2015

Viability of cumulus cells is associated with basal AMH levels in assisted reproduction.

Eur J Obstet Gynecol Reprod Biol 2014 Dec 20;183:59-63. Epub 2014 Oct 20.

Landes- Frauen- und Kinderklinik, Departement of Gynecological Endocrinology and Kinderwunsch Zentrum Linz, Krankenhausstr. 26-30, Linz, Upper Austria, Austria; Johannes Kepler University, Faculty of Medicine, Altenberger Straße 69, Linz, Upper Austria, Austria.

Objective(s): An interesting non-invasive approach to select embryos for transfer is analyzing the health state of somatic granulosa cells surrounding the oocyte addressing their mutual dependence. This prospective study was set up to analyse whether the DNA integrity of cumulus cells correlates with preimplantation development and basal AMH levels.

Study Design: Therefore, 56 patients who gave written consent were enrolled. Sequential denudation of the cumulus-oocyte-complexes was performed in order to separate corona radiata from outer cumulus cells. DNA integrity of both cell types was analysed using a modified chromatin dispersion test.

Results: The percentage of viable corona radiata cells per patient showed a linear correlation to blastulation (P<0.05). These innermost cells showed significantly lower rates of strand breaks (P<0.01) as compared to outer cumulus cells. Age-corrected AMH was significantly associated with the DNA integrity of outer cumulus cells (P<0.05).

Conclusion(s): For the first time it could be shown that in fact clinical embryologists deal with two different entities of cumulus cells, inner and outer ones. It seems that any protective mechanism of the female gamete follows an outward gradient, so that negative effects, e.g. apoptosis, may impair outer cumulus cells first. Age-corrected AMH reflects quality of these outer cumulus cells.

Keywords: AMH; Corona radiata cells; DNA fragmentation; Outer cumulus cells; SCD test.
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http://dx.doi.org/10.1016/j.ejogrb.2014.10.015DOI Listing
December 2014

Identification of risk genes for autism spectrum disorder through copy number variation analysis in Austrian families.

Neurogenetics 2014 May 19;15(2):117-27. Epub 2014 Mar 19.

Neurogenetics Section, R-30, The Campbell Family Brain Research Institute, The Centre for Addiction & Mental Health (CAMH), 250 College Street, Toronto, ON, M5T 1R8, Canada.

Autism or autism spectrum disorder (ASD) is a range of neurodevelopmental disorders starting in early childhood and is characterized by impairments in communication and reciprocal social interaction and presence of restricted and repetitive patterns of behavior. The contribution of genetic factors to autism is clear in twin and family studies. It is apparent that, overall, ASD is a complex non-Mendelian disorder. Recent studies suggest that copy number variations (CNVs) play a significant role in the etiology of ASD. For the current work, we recruited 245 family members from 73 ASD families from Styria, Austria. The DNA from probands was genotyped with Affymetrix single nucleotide polymorphism (SNP) 6.0 microarrays to screen for CNVs in their genomes. Analysis of the microarray data was performed using three different algorithms, and a list of stringent calls was compared to existing CNV data from over 2,357 controls of European ancestry. For stringent calls not present in controls, quantitative real-time PCR (qRT-PCR) was used to validate the CNVs in the probands and in their family members. Twenty-two CNVs were validated from this set (five of which are apparently de novo), many of which appear likely to disrupt genes that may be considered as good candidates for neuropsychiatric disorders, including DLG2, S100B, ARX, DIP2A, HPCAL1, and GPHN. Several others disrupt genes that have previously been implicated in autism, such as BDNF, AUTS2, DPP6, and C18orf22, and our data add to the growing evidence of their involvement in ASD.
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http://dx.doi.org/10.1007/s10048-014-0394-0DOI Listing
May 2014

Three different profiles: early socio-communicative capacities in typical Rett syndrome, the preserved speech variant and normal development.

Dev Neurorehabil 2014 Feb 2;17(1):34-8. Epub 2013 Oct 2.

Institute of Physiology (Research Unit iDN - interdisciplinary Developmental Neuroscience; IN:spired), Center for Physiological Medicine, Medical University of Graz , Austria .

Background And Aims: This is the first study aiming to compare pre-diagnostic socio-communicative development of a female with typical Rett syndrome (RTT), a female with the preserved speech variant of RTT (PSV) and a control toddler.

Methods: We analysed 1275 min of family videos at the participants' age between 9 and 24 months and used the Inventory of Potential Communicative Acts (IPCA) to delineate their repertoires of communicative forms and functions.

Results: The results revealed different profiles for the three different conditions. The repertoire of communicative gestures and (pre)linguistic vocalizations was most comprehensive in the control toddler, followed by the female with PSV and the female with RTT.

Conclusion: These findings contribute to the growing knowledge about early developmental abnormalities in RTT. In order to define distinctive profiles for typical and atypical RTT and evaluate their specificity, a larger body of evidence is needed.
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http://dx.doi.org/10.3109/17518423.2013.837537DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5951276PMC
February 2014

Rare exonic deletions implicate the synaptic organizer Gephyrin (GPHN) in risk for autism, schizophrenia and seizures.

Hum Mol Genet 2013 May 7;22(10):2055-66. Epub 2013 Feb 7.

The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children,Toronto, ON, Canada.

The GPHN gene codes for gephyrin, a key scaffolding protein in the neuronal postsynaptic membrane, responsible for the clustering and localization of glycine and GABA receptors at inhibitory synapses. Gephyrin has well-established functional links with several synaptic proteins that have been implicated in genetic risk for neurodevelopmental disorders such as autism spectrum disorder (ASD), schizophrenia and epilepsy including the neuroligins (NLGN2, NLGN4), the neurexins (NRXN1, NRXN2, NRXN3) and collybistin (ARHGEF9). Moreover, temporal lobe epilepsy has been linked to abnormally spliced GPHN mRNA lacking exons encoding the G-domain of the gephyrin protein, potentially arising due to cellular stress associated with epileptogenesis such as temperature and alkalosis. Here, we present clinical and genomic characterization of six unrelated subjects, with a range of neurodevelopmental diagnoses including ASD, schizophrenia or seizures, who possess rare de novo or inherited hemizygous microdeletions overlapping exons of GPHN at chromosome 14q23.3. The region of common overlap across the deletions encompasses exons 3-5, corresponding to the G-domain of the gephyrin protein. These findings, together with previous reports of homozygous GPHN mutations in connection with autosomal recessive molybdenum cofactor deficiency, will aid in clinical genetic interpretation of the GPHN mutation spectrum. Our data also add to the accumulating evidence implicating neuronal synaptic gene products as key molecular factors underlying the etiologies of a diverse range of neurodevelopmental conditions.
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http://dx.doi.org/10.1093/hmg/ddt056DOI Listing
May 2013

MODY type 2 in Greig cephalopolysyndactyly syndrome (GCPS) as part of a contiguous gene deletion syndrome.

Am J Med Genet A 2011 Oct;155A(10):2469-72

Pediatric Endocrinology Unit, Kaplan Medical Center, Rehovot, Israel.

Maturity-onset diabetes of the young type 2 (MODY2) is a form of monogenic diabetes, characterized by mild fasting hyperglycemia. MODY2 is caused by heterozygous mutations in the GCK gene that encodes the glucokinase enzyme. We describe the clinical features and the underlying genetic defect of MODY2 in a patient with atypical Greig cephalopolysyndactyly syndrome (GCPS). The patient presented with the limb formation and the craniofacial developmental abnormalities typical to GCPS, in addition to mental retardation and epilepsy (assigned as atypical syndrome). Fasting hyperglycemia in the diabetic range, impaired glucose tolerance, and lack of diabetes autoantibodies were compatible with MODY2. In order to delineate the genetic aberrations relevant both to MODY2 and Greig syndrome in this patient, we performed cytogenetic analysis, real-time PCR of the GCK gene, and comparative genomic hybridization (CGH) array. Cytogenetic study has shown a microscopic detectable deletion in the 7p13-15 chromosomal region. Real-time PCR demonstrated a deletion of the GCK gene in the patient but not her parents, and CGH array revealed a deleted region of approximately 12 Mb in the 7p13-15 region. This deleted region included GLI3 and GCK genes (where heterozygous mutations cause GCPS and MODY2, respectively), and many other contiguous genes. Our patient manifests a unique form of MODY2, where GCK gene deletion is part of a large deleted segment in the 7p13-15 chromosomal region.
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http://dx.doi.org/10.1002/ajmg.a.33829DOI Listing
October 2011

Prenatal detection of chromosome aneuploidy by quantitative-fluorescence PCR.

Methods Mol Biol 2011 ;688:207-26

Cytogenetics Department, Guy's Hospital, London, UK.

QF-PCR refers to the amplification of chromosome-specific polymorphic microsatellite markers using fluorescence-labelled primers, followed by semi-quantitative analysis of the products on a genetic analyser to determine copy number and/or imbalances of specific chromosomal material. This approach is now widely used for rapid prenatal diagnosis of the common trisomies. In addition, it can successfully detect maternal cell contamination and mosaicism in prenatal material.
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http://dx.doi.org/10.1007/978-1-60761-947-5_14DOI Listing
January 2011

Automatic retrieval of single microchimeric cells and verification of identity by on-chip multiplex PCR.

J Cell Mol Med 2010 Apr 19;14(4):954-69. Epub 2009 May 19.

Institute of Cell Biology, Histology and Embryology, Center for Molecular Medicine, Medical University of Graz, Graz, Austria.

The analysis of rare cells is not an easy task. This is especially true when cells representing a fetal microchimerism are to be utilized for the purpose of non-invasive prenatal diagnosis because it is both imperative and difficult to avoid contaminating the minority of fetal cells with maternal ones. Under these conditions, even highly specific biochemical markers are not perfectly reliable. We have developed a method to verify the genomic identity of rare cells that combines automatic screening for enriched target cells (based on immunofluorescence labelling) with isolation of single candidate microchimeric cells (by laser microdissection and subsequent laser catapulting) and low-volume on-chip multiplex PCR for DNA fingerprint analysis. The power of the method was tested using samples containing mixed cells of related and non-related individuals. Single-cell DNA fingerprinting was successful in 74% of the cells analysed (55/74), with a PCR efficiency of 59.2% (860/1452) for heterozygous loci. The identification of cells by means of DNA profiling was achieved in 100% (12/12) of non-related cells in artificial mixtures and in 86% (37/43) of cells sharing a haploid set of chromosomes and was performed on cells enriched from blood and cells isolated from tissue. We suggest DNA profiling as a standard for the identification of microchimerism on a single-cell basis.
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http://dx.doi.org/10.1111/j.1582-4934.2009.00784.xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3823127PMC
April 2010

Characterization of a de novo translocation t(5;18)(q33.1;q12.1) in an autistic boy identifies a breakpoint close to SH3TC2, ADRB2, and HTR4 on 5q, and within the desmocollin gene cluster on 18q.

Am J Med Genet B Neuropsychiatr Genet 2009 Sep;150B(6):817-26

Centre for Addiction and Mental Health, Toronto, Ontario, Canada.

We have recently reported the identification of a de novo balanced translocation t(5;18)(q33.1;q12.1) in a boy with autism. Here we discuss the identification of the breakpoints on chromosomes 5 and 18, and subsequent genomic and candidate gene analyses. The 18q breakpoint lies between desmocollin genes DSC1 and DSC2. The chromosome 5 breakpoint lies at the 3' end of the SH3TC2 gene and distal to beta-adrenergic receptor gene ADRB2 and serotonin receptor gene HTR4. We hypothesized that the transcription of one (or more) of these genes is affected by the translocation by position effect. Looking at allele-specific gene expression for the genes at the 5q locus, we were able to determine that ADRB2 is expressed from both the normal and derivative alleles. Due to the lack of expression in available tissues or lack of available informative transcribed SNPs, we were unable to exclude the involvement of SH3TC2 and HTR4 due to position effect. However, we determined that both DSC1 and DSC2 are only transcribed from the normal chromosome 18 in lymphocytes from the proband. This monoallelic expression of DSC2 may put the patient at risk for arrythmogenic right ventricular cardiomyopathy. Desmocollin genes encode cell-adhesion molecules, and are also highly expressed in brain regions, and thus may also be important for normal neuronal functioning. While a role for SH3TC2, ADRB2, and HTR4 as putative candidate genes for autism cannot be discounted, a role for the desmocollin genes at the 18q breakpoint should also be considered.
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http://dx.doi.org/10.1002/ajmg.b.30903DOI Listing
September 2009

Prenatal detection of chromosome aneuploidy by quantitative fluorescence PCR.

Methods Mol Biol 2008 ;444:71-94

Cytogenetics Department, Guy's Hospital, London, UK.

Autosomal chromosome aneuploid pregnancies that survive to term, namely, trisomies 13, 18, and 21, account for 89% of chromosome abnormalities with a severe phenotype. They are normally detected by full karyotype analysis of cultured cells. The average reporting time for a prenatal karyotype analysis is approximately 14 days, and in recent years, there has been increasing demand for more rapid prenatal results with respect to the common chromosome aneuploidies, to relieve maternal anxiety and facilitate options in pregnancy. The rapid tests that have been developed negate the requirement for cultured cells, instead directly testing cells from the amniotic fluid or chorionic villus sample, with the aim of generating results within 48 h of sample receipt. Interphase fluorescence in situ hybridization is the method of choice in some genetic laboratories, usually because the expertise and equipment are readily available. However, a quantitative fluorescence (QF)-PCR-based approach is more suited to a high-throughput diagnostic service. This approach has been investigated in a small number of pilot studies and reported as a clinical diagnostic service in many studies. It may be used as a stand-alone test or as an adjunct test to full karyotype analysis, which subsequently confirms the rapid result and scans for other chromosome abnormalities not detected by the QF-PCR assay.
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http://dx.doi.org/10.1007/978-1-59745-066-9_6DOI Listing
June 2008

An X-linked myopathy with postural muscle atrophy and generalized hypertrophy, termed XMPMA, is caused by mutations in FHL1.

Am J Hum Genet 2008 Jan;82(1):88-99

Neurogenetics Section, The Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, M5T 1R8, Canada.

We have identified a large multigenerational Austrian family displaying a novel form of X-linked recessive myopathy. Affected individuals develop an adult-onset scapulo-axio-peroneal myopathy with bent-spine syndrome characterized by specific atrophy of postural muscles along with pseudoathleticism or hypertrophy and cardiac involvement. Known X-linked myopathies were excluded by simple-tandem-repeat polymorphism (STRP) and single-nucleotide polymorphism (SNP) analysis, direct gene sequencing, and immunohistochemical analysis. STRP analysis revealed significant linkage at Xq25-q27.1. Haplotype analysis based on SNP microarray data from selected family members confirmed this linkage region on the distal arm of the X chromosome, thereby narrowing down the critical interval to 12 Mb. Sequencing of functional candidate genes led to the identification of a missense mutation within the four and a half LIM domain 1 gene (FHL1), which putatively disrupts the fourth LIM domain of the protein. Mutation screening of FHL1 in a myopathy family from the UK exhibiting an almost identical phenotype revealed a 3 bp insertion mutation within the second LIM domain. FHL1 on Xq26.3 is highly expressed in skeletal and cardiac muscles. Western-blot analysis of muscle biopsies showed a marked decrease in protein expression of FHL1 in patients, in concordance with the genetic data. In summary, we have to our knowledge characterized a new disorder, X-linked myopathy with postural muscle atrophy (XMPMA), and identified FHL1 as the causative gene. This is the first FHL protein to be identified in conjunction with a human genetic disorder and further supports the role of FHL proteins in the development and maintenance of muscle tissue. Mutation screening of FHL1 should be considered for patients with uncharacterized myopathies and cardiomyopathies.
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http://dx.doi.org/10.1016/j.ajhg.2007.09.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2253986PMC
January 2008

Molecular and genomic studies of IMMP2L and mutation screening in autism and Tourette syndrome.

Mol Genet Genomics 2007 Jan 17;277(1):71-81. Epub 2006 Oct 17.

Institute of Medical Biology and Human Genetics, Medical University of Graz, Harrachgasse 21/8, 8010, Graz, Austria.

We recently reported the disruption of the inner mitochondrial membrane peptidase 2-like (IMMP2L) gene by a chromosomal breakpoint in a patient with Gilles de la Tourette syndrome (GTS). In the present study we sought to identify genetic variation in IMMP2L, which, through alteration of protein function or level of expression might contribute to the manifestation of GTS. We screened 39 GTS patients, and, due to the localization of IMMP2L in the critical region for the autistic disorder (AD) locus on chromosome 7q (AUTS1), 95 multiplex AD families; however, no coding mutations were found in either GTS or AD patients. In addition, no parental-specific expression of IMMP2L was detected in somatic cell hybrids containing human chromosome 7 and human cell lines carrying a maternal uniparental disomy for chromosome 7 (mUPD7). Despite the fact that no deleterious mutations in IMMPL2 (other than the inverted duplication identified previously) were identified in either GTS or AD, this gene cannot be excluded as a possible rare cause of either disorder.
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http://dx.doi.org/10.1007/s00438-006-0173-1DOI Listing
January 2007

Genomic analysis of five chromosome 7p deletion patients with Greig cephalopolysyndactyly syndrome (GCPS).

Eur J Med Genet 2006 Jul-Aug;49(4):338-45. Epub 2005 Nov 28.

Institute of Medical Biology and Human Genetics, Medical University of Graz, Graz 8010, Austria.

Chromosomal deletions on chromosome 7p are associated with Greig cephalopolysyndactyly syndrome (GCPS, OMIM 175700) a syndrome affecting the development of the skull, face, and limbs. We have compared data from molecular cytogenetic and genetic analyses with clinical symptoms from five previously published GCPS deletion patients, including a pair of monozygotic twins. The genomic DNA of the probands and their parents, as well as the DNA from monoallelic cell lines of two patients, was analyzed using microsatellite markers. In some cases (e.g. where the microsatellite studies were uninformative) we also used fluorescence in situ hybridization (FISH) with bacterial artificial chromosomes (BAC) probes. The fine mapping results of the deletions and genomic data from chromosome 7, were compared to the clinical symptoms. Common breakpoint sequences or mutation hotspots were not observed. Mutation screening for PGAM2, which is responsible for a form of myopathy with recessive inheritance, was performed in all patients. Loss of heterozygosity for known genes with dominant inheritance, such as the glucokinase gene (GCK), which, when mutated or haploinsufficient, is responsible for maturity-onset diabetes of the young, type II (MODY2, OMIM 125851), was identified and included in a genetic counseling of the patients' families.
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http://dx.doi.org/10.1016/j.ejmg.2005.10.133DOI Listing
September 2006

Phenotypic and molecular characterisation of a de novo 5q deletion that includes the APC gene.

J Hum Genet 2006 20;51(2):141-146. Epub 2005 Dec 20.

Institute of Medical Biology and Human Genetics, Medical University Graz, Harrachgasse 21/8, 8010, Graz, Austria.

We report on a 12-year-old female patient with mild dysmorphic signs, including bilateral epicanthal folds, low-set dysplastic ears, a short nose with anteverted nostrils, conically shaped fingers, generalised increase of subcutaneous fat, multiple fine venous teleangiectasia on her back, mild pectus carinatum, and a general muscular hypotonia. Cytogenetic analysis and fluorescence in situ hybridisation (FISH) studies using region-specific BAC and YAC clones indicated a de novo interstitial deletion of the long arm of chromosome 5, resulting in monosomy 5q21.1-q23.1. Molecular analysis of polymorphic markers helped to narrow down the breakpoints and demonstrated that the derivative chromosome 5 is of paternal origin. By using the same panel of polymorphic markers, a reinvestigation of a similar, already published, 5q deletion case [Raedle et al. (2001) Am J Gastroenterol 96:3016-3020] was performed, allowing a more detailed genotype-phenotype correlation. Phenotypic classification was also carried out. Several known genes, including APC and MCC, were found to map to the common deleted genomic segment. Genetic counselling based on the molecular analysis data was performed for the index family.
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http://dx.doi.org/10.1007/s10038-005-0333-xDOI Listing
October 2006

Williams-Beuren syndrome associated with caudal regression syndrome and coagulopathy--a case report.

J Pediatr Surg 2005 Nov;40(11):e47-50

Department of Pediatric Surgery, Medical University of Graz, 8036 Graz, Austria.

Williams-Beuren syndrome is a genetic disorder caused by a heterozygous deletion at 7q11.23. The present report describes a female patient with Williams-Beuren syndrome combined with caudal regression syndrome and two forms of coagulopathy. Besides the typical developmental abnormalities such as mental and growth retardation, a distinctive facial appearance, and cardiovascular anomalies, our patient showed fusion of fourth and fifth lumbar vertebra and a sacrococcygeal agenesis. Blood coagulation tests revealed a deficiency of coagulation factor XI and XII. Magnetic resonance imaging angiography showed multiple vascular stenoses mainly in the abdominal aorta and its major branches as a consequence of the insufficient elastin gene. Previous reports identified a deletion of HLXB9 as a possible genetic cause of the caudal regression syndrome, which could not be identified in the present case. This unusual combination of the above-mentioned genetic disorders has not been published so far.
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http://dx.doi.org/10.1016/j.jpedsurg.2005.07.048DOI Listing
November 2005

Compound heterozygosity (G71R/R140H) in the lecithin:cholesterol acyltransferase (LCAT) gene results in an intermediate phenotype between LCAT-deficiency and fish-eye disease.

Atherosclerosis 2006 Jul 10;187(1):101-9. Epub 2005 Oct 10.

Department of Molecular Biology and Biochemistry, Center for Molecular Medicine, Medical University of Graz, Harrachgasse 21, A-8010 Graz, Austria.

The esterification of free cholesterol (FC) in plasma, catalyzed by the enzyme lecithin:cholesterol acyltransferase (LCAT; EC 2.3.1.43), is a key process in lipoprotein metabolism. The resulting cholesteryl esters (CE) represent the main core lipids of low (LDL) and high density lipoproteins (HDL). Primary (familial) LCAT-deficiency (FLD) is a rare autosomal recessive genetic disease caused by the complete or near absence of LCAT activity. In fish-eye disease (FED), residual LCAT activity is still detectable. Here, we describe a 32-year-old patient with corneal opacity, very low LCAT activity, reduced amounts of CE (low HDL-cholesterol level), and elevated triglyceride (TG) values. The lipoprotein pattern was abnormal with regard to lipoprotein composition and concentration, but distinct lipoprotein classes were still present. Despite of typical features of glomerular proteinuria, creatinine clearance was normal. DNA sequencing and restiction fragment analyses revealed two separate mutations in the patient's LCAT gene: a previously described G to A transition in exon 4 converting Arg140 to His, inherited from his mother, and a novel G to C transversion in exon 2 converting Gly71 to Arg, inherited from his father, indicating that M.P. was a compound heterozygote. Determination of enzyme activities of recombinant LCAT proteins obtained upon transfection of COS-7 cells with plasmids containing G71R-LCAT or wild-type LCAT cDNA revealed very low alpha- and absence of beta-LCAT activity for the G71R mutant. The identification of the novel G71R LCAT mutation supports the proposed molecular model for the enzyme implying that the "lid" domain at residues 50-74 is involved in enzyme:substrate interaction. Our data are in line with the hypothesis that a key event in the etiology of FLD is the loss of distinct lipoprotein fractions.
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http://dx.doi.org/10.1016/j.atherosclerosis.2005.08.038DOI Listing
July 2006

Cloning, genomic structure, and expression profiles of TULIP1 (GARNL1), a brain-expressed candidate gene for 14q13-linked neurological phenotypes, and its murine homologue.

Genomics 2004 Sep;84(3):577-86

Institute of Medical Biology and Human Genetics, Medical University of Graz, Harrachgasse 21/8, A-8010 Graz, Austria.

Previously, we have described the clinical and molecular characterization of a de novo 14q13.1-q21.1 microdeletion, less than 3.5 Mb in size, in a patient with severe microcephaly, psychomotor retardation, and other clinical anomalies. Here we report the characterization of the genomic structure of the human tuberin-like protein gene 1 (TULIP1; approved gene symbol GARNL1), a CpGisland-associated, brain-expressed candidate gene for the neurological findings in our patient, and its murine homologue. The human TULIP1 gene was mapped to chromosome band 14q13.2 by fluorescence in situ hybridization of BAC clone RP11-355C3 (GenBank Accession No. AL160231), containing the 3' region of the gene. TULIP1 spans about 271 kb of human genomic DNA and is divided into 41 exons. An untranscribed, processed pseudogene of TULIP1 was found on human chromosome band 9q31.1. The active locus TULIP1, encoding a predicted protein of 2036 amino acids, is expressed ubiquitously in pre- and postnatal human tissues. The murine homologue Tulip1 spans about 220 kb of mouse genomic DNA and is also divided into 41 exons, encoding a predicted protein of 2035 amino acids. No pseudogene could be found in the available mouse sequence data. Several splicing variants were found. Considering the location, expression profile, and predicted function, TULIP1 is a strong candidate for several neurological features seen in 14q deletion patients. Additionally we searched for mutations in the coding region of TULIP1 in subjects from a family with idiopathic basal ganglia calcification (IBGC; Fahr disease), previously linked to chromosome 14q. We identified two novel SNPs in the intron-exon boundaries; however, they did not segregate only with affected subjects in the predicted model of an autosomal dominant disease such as IBGC.
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http://dx.doi.org/10.1016/j.ygeno.2004.04.013DOI Listing
September 2004

Heterozygous missense mutations in BSCL2 are associated with distal hereditary motor neuropathy and Silver syndrome.

Nat Genet 2004 Mar 22;36(3):271-6. Epub 2004 Feb 22.

Institute of Medical Biology and Human Genetics, Medical University Graz, Harrachgasse 21/8, A-8010 Graz, Austria.

Distal hereditary motor neuropathy (dHMN) or distal spinal muscular atrophy (OMIM #182960) is a heterogeneous group of disorders characterized by an almost exclusive degeneration of motor nerve fibers, predominantly in the distal part of the limbs. Silver syndrome (OMIM #270685) is a rare form of hereditary spastic paraparesis mapped to chromosome 11q12-q14 (SPG17) in which spasticity of the legs is accompanied by amyotrophy of the hands and occasionally also the lower limbs. Silver syndrome and most forms of dHMN are autosomal dominantly inherited with incomplete penetrance and a broad variability in clinical expression. A genome-wide scan in an Austrian family with dHMN-V (ref. 4) showed linkage to the locus SPG17, which was confirmed in 16 additional families with a phenotype characteristic of dHMN or Silver syndrome. After refining the critical region to 1 Mb, we sequenced the gene Berardinelli-Seip congenital lipodystrophy (BSCL2) and identified two heterozygous missense mutations resulting in the amino acid substitutions N88S and S90L. Null mutations in BSCL2, which encodes the protein seipin, were previously shown to be associated with autosomal recessive Berardinelli-Seip congenital lipodystrophy (OMIM #269700). We show that seipin is an integral membrane protein of the endoplasmic reticulum (ER). The amino acid substitutions N88S and S90L affect glycosylation of seipin and result in aggregate formation leading to neurodegeneration.
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http://dx.doi.org/10.1038/ng1313DOI Listing
March 2004