Myotilin gene duplication causing late-onset myotilinopathy.

Background: myotilinopathy is a very rare inherited muscle disease that belongs to the group of myofibrillar myopathies. These diseases share a common alteration of the sarcomere organization at the level of the Z disk resulting in pathological protein aggregation, autophagic abnormalities, and ultimately muscle degeneration. Most reported cases are due to dominant missense mutations in the MYOT gene, two of which are largely recurrent.

SMCHD1 genetic variants in type 2 facioscapulohumeral dystrophy and challenges in predicting pathogenicity and disease penetrance.

The molecular diagnosis of type 1 facioscapulohumeral muscular dystrophy (FSHD1) relies on the detection of a shortened D4Z4 array at the 4q35 locus. Until recently, the diagnosis of FSHD2 relied solely on the absence of a shortened D4Z4 allele in clinically affected patients. It is now established that most FSHD2 cases carry a heterozygous variant in the SMCHD1 gene.

Spinal muscular atrophy is also a disorder of spermatogenesis.

Background: Spinal muscular atrophy (SMA) patients benefit from pre-mRNA splicing modifiers targeting the SMN2 gene, which aims to increase functional SMN production. The animal toxicity affecting spermatogenesis associated with one such treatment raised questions about male SMA patients' spermatogenesis.

Methods: This descriptive, cross-sectional study was conducted from June 2022 to July 2023.