European Journal of Human Genetics最新文献

This review article presents key guidelines for developing an effective and structured Genetic Counselling Supervision (GCS) framework for Europe. Based on international best practices and the authors' research at both the European and national levels, these 21 guidelines aim to provide a structured approach that will promote ethical standards, enhance professional well-being, and improve service quality, ensuring the successful implementation of GCS across healthcare settings in Europe. By doing so, this article seeks to address a critical gap identified by professionals and policymakers regarding the lack of clear guidance on what should drive genetic counselling supervision.

Monoallelic germline DDX41 pathogenic variants (PV) are responsible for the most frequent monogenic predisposition to myeloid neoplasms (MN), i.e., to myelodysplastic syndrome and acute myeloid leukemia. MN are rare clonal diseases affecting hematopoietic tissues, and curative approaches frequently implicate hematopoietic stem cell transplantation, requesting testing for relatives of DDX41-mutated MN patients. Establishing the penetrance of germline DDX41 PV is crucial to determine how to monitor the unaffected relatives who carry the familial DDX41 PV. Our study aims to assess the risk of MN in relatives of affected DDX41 carriers using the Genotype-Restricted-Likelihood (GRL) approach. We identified 63 families with probands carrying a germline DDX41 PV (ACMG class 4 or class 5 variant) affected with MN, from 11 French centers. One hundred and sixty relatives, including 73 males (46%), were genotyped at the median age of 51 [range: 15-84] years, 80 of them (50%) being carriers of the familial DDX41 PV. The cumulative risk of MN at 70 years for DDX41 PV carriers was estimated at 19.5% [95% CI: 5.8%-62.5%], corresponding to a relative risk compared to the general population of 55 [95% CI: 16.4-176.5]. This risk appeared higher in males, although the difference did not reach statistical significance. Based on these findings, we suggest yearly complete blood count from the age of 50 for DDX41 PV carriers. Of note, we observed cases before the age of 50 in females, which could suggest sex-differentiated monitoring.

Excitation-contraction (EC) coupling is an essential process for skeletal muscle function. Pathogenic variants in different EC coupling components have previously been associated with various neuromuscular disorders. In this study we aimed to identify the genetic etiology of a muscular condition characterized by early-onset muscle weakness, elevated CK, ptosis and low body weight, which was observed in three individuals from two unrelated consanguineous families. Exome sequencing (ES) performed in multiple individuals of one family, and ES in combination with SNP array-based homozygosity mapping in the proband of the other family, revealed different homozygous loss-of-function variants in the second exon of CACNB1 in the affected individuals from each family. CACNB1 encodes the β1 subunit of the skeletal muscle dihydropyridine receptor (DHPR), a voltage-gated Ca²⁺ channel with a major role in EC coupling. Molecular impact of the identified variants was assessed in LHCN-M2 human myoblasts. Long-read RNA sequencing in LHCN-M2 wild-type myotubes showed that in differentiated skeletal muscle cells virtually all CACNB1 transcript isoforms contain exon 2 and will therefore be affected by genetic variants in this exon. Pathogenicity of the identified CACNB1 variants was further validated by replicating one of them (c.85-1G>A) in LHCN-M2 cells using CRISPR-Cas9-mediated base-editing. Analysis of LHCN-M2 edited myotubes demonstrated that in addition to the loss of β1 subunits, these cells displayed severely reduced protein levels of α1S, the pore-forming subunit of DHPR. We conclude that pathogenic variants in CACNB1 cause a new congenital muscular disorder.