Publications by authors named "Maude Grelet"

5 Publications

  • Page 1 of 1

Heterozygous HTRA1 nonsense or frameshift mutations are pathogenic.

Brain 2021 Jul 16. Epub 2021 Jul 16.

AP-HP, Service de Génétique Moléculaire Neurovasculaire, Hôpital Saint-Louis, France.

Heterozygous missense HTRA1 mutations have been associated with an autosomal dominant cerebral small vessel disease whereas the pathogenicity of heterozygous HTRA1 stop codon variants is unclear. We performed a targeted high throughput sequencing of all known cerebral small vessel disease genes, including HTRA1, in 3,853 unrelated consecutive CSVD patients referred for molecular diagnosis. The frequency of heterozygous HTRA1 mutations leading to a premature stop codon in this patient cohort was compared with their frequency in large control databases. An analysis of HTRA1 messenger RNA was performed in several stop codon carrier patients. Clinical and neuroimaging features were characterized in all probands. Twenty unrelated patients carrying a heterozygous HTRA1 variant leading to a premature stop codon were identified. A highly significant difference was observed when comparing our patient cohort with control databases (gnomAD v3.1.1 (p = 3.12 x 10-17, OR = 21.9), TOPMed freeze 5 (p = 7.6 x 10-18, OR = 27.1) and 1000 Genomes (p = 1.5 x 10-5). Messenger RNA analysis performed in eight patients showed a degradation of the mutated allele strongly suggesting a haploinsufficiency. Clinical and neuroimaging features are similar to those previously reported in heterozygous missense mutation carriers, except for penetrance, which seems lower. Altogether, our findings strongly suggest that heterozygous HTRA1 stop codons are pathogenic through a haploinsufficiency mechanism. Future work will help to estimate their penetrance, an important information for genetic counseling.
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http://dx.doi.org/10.1093/brain/awab271DOI Listing
July 2021

Fetal megacystis-microcolon: Genetic mutational spectrum and identification of PDCL3 as a novel candidate gene.

Clin Genet 2020 09 4;98(3):261-273. Epub 2020 Aug 4.

Service de génétique, Hôpital Nord CHU Saint-Etienne, Saint Etienne, France.

Megacystis-microcolon-intestinal-hypoperistalsis syndrome (MMIHS) is a severe congenital visceral myopathy characterized by an abdominal distension due to a large non-obstructed urinary bladder, a microcolon and intestinal hypo- or aperistalsis. Most of the patients described to date carry a sporadic heterozygous variant in ACTG2. More recently, recessive forms have been reported and mutations in MYH11, LMOD1, MYLK and MYL9 have been described at the molecular level. In the present report, we describe five patients carrying a recurrent heterozygous variant in ACTG2. Exome sequencing performed in four families allowed us to identify the genetic cause in three. In two families, we identified variants in MMIHS causal genes, respectively a nonsense homozygous variant in MYH11 and a previously described homozygous deletion in MYL9. Finally, we identified compound heterozygous variants in a novel candidate gene, PDCL3, c.[143_144del];[380G>A], p.[(Tyr48Ter)];[(Cys127Tyr)]. After cDNA analysis, a complete absence of PDLC3 expression was observed in affected individuals, indicating that both mutated transcripts were unstable and prone to mediated mRNA decay. PDCL3 encodes a protein involved in the folding of actin, a key step in thin filament formation. Presumably, loss-of-function of this protein affects the contractility of smooth muscle tissues, making PDCL3 an excellent candidate gene for autosomal recessive forms of MMIHS.
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http://dx.doi.org/10.1111/cge.13801DOI Listing
September 2020

Outcomes of 4 years of molecular genetic diagnosis on a panel of genes involved in premature aging syndromes, including laminopathies and related disorders.

Orphanet J Rare Dis 2019 12 11;14(1):288. Epub 2019 Dec 11.

Department of Medical Genetics, Assistance Publique Hopitaux de Marseille, Marseille, France.

Background: Segmental progeroid syndromes are a heterogeneous group of rare and often severe genetic disorders that have been studied since the twentieth century. These progeroid syndromes are defined as segmental because only some of the features observed during natural aging are accelerated.

Methods: Since 2015, the Molecular Genetics Laboratory in Marseille La Timone Hospital proposes molecular diagnosis of premature aging syndromes including laminopathies and related disorders upon NGS sequencing of a panel of 82 genes involved in these syndromes. We analyzed the results obtained in 4 years on 66 patients issued from France and abroad.

Results: Globally, pathogenic or likely pathogenic variants (ACMG class 5 or 4) were identified in about 1/4 of the cases; among these, 9 pathogenic variants were novel. On the other hand, the diagnostic yield of our panel was over 60% when the patients were addressed upon a nosologically specific clinical suspicion, excepted for connective tissue disorders, for which clinical diagnosis may be more challenging. Prenatal testing was proposed to 3 families. We additionally detected 16 variants of uncertain significance and reclassified 3 of them as benign upon segregation analysis in first degree relatives.

Conclusions: High throughput sequencing using the Laminopathies/ Premature Aging disorders panel allowed molecular diagnosis of rare disorders associated with premature aging features and genetic counseling for families, representing an interesting first-level analysis before whole genome sequencing may be proposed, as a future second step, by the National high throughput sequencing platforms ("Medicine France Genomics 2025" Plan), in families without molecular diagnosis.
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http://dx.doi.org/10.1186/s13023-019-1189-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6907233PMC
December 2019

SATB2-associated syndrome: first report of a gonadal and somatic mosaicism for an intragenic copy number variation.

Clin Dysmorphol 2019 Oct;28(4):205-210

APHM, CHU Timone Enfants, Département de Génétique Médicale.

Gonadal mosaicism has been reported in a variety of dominant or X-linked conditions and should be considered in all cases of apparent de-novo variation. Recently, some cases of supposed parental germline mosaicism have been shown to result from low-level somatic mosaicism. In most of the cases, mosaicism has been reported for pathogenic single nucleotide variants with only a few cases of copy number variation mosaicism described so far. Herein, we present the first case of parental somatic and gonadal copy number variation mosaicism in the SATB2 gene. We report three brothers presenting with the SATB2-associated syndrome. They all carry the same 121-kb heterozygous intragenic deletion of SATB2. Parental somatic mosaicism was detected by array-comparative genomic hybridization on a maternal blood sample and confirmed by Fluorescence in situ hybridization analysis on blood and buccal cells. This clinical report highlights the importance of investigating for parental somatic mosaicism to estimate the proper recurrence risk for subsequent pregnancy.
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http://dx.doi.org/10.1097/MCD.0000000000000293DOI Listing
October 2019

Analysis of HOXB1 gene in a cohort of patients with sporadic ventricular septal defect.

Mol Biol Rep 2018 Oct 19;45(5):1507-1513. Epub 2018 Jun 19.

Aix Marseille Université, INSERM U1251, MMG, Marseille, France.

Ventricular septal defect (VSD) including outlet VSD of double outlet right ventricle (DORV) and perimembranous VSD are among the most common congenital heart diseases found at birth. HOXB1 encodes a homeodomain transcription factor essential for normal cardiac outflow tract development. The aim of the present study was to investigate the possible genetic effect of sequence variations in HOXB1 on VSD. The coding regions and splice junctions of the HOXB1 gene were sequenced in 57 unrelated VSD patients. As a result, a homozygous c.74_82dup (p.Pro28delinsHisSerAlaPro) variant was identified in one individual with DORV. We also identified five previously reported polymorphisms (rs35114525, rs12946855, rs14534040, rs12939811, and rs7207109) in 18 patients (12 DORV and 6 perimembranous VSD). Our study did not show any pathogenic alterations in the coding region of HOXB1 among patients with VSD. To our knowledge this is the first study investigating the role of HOXB1 in nonsyndromic VSD, which provide more insight on the etiology of this disease.
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http://dx.doi.org/10.1007/s11033-018-4212-xDOI Listing
October 2018
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