Clinicians and geneticists from the Filnemus network, including members of the Institute of Myology, and from London pooled data from patients presenting with a picture compatible with spinal muscular atrophy, but where an SMN1 gene anomaly had been formally excluded:
- 71 patients from 65 families were included in the study,
- phenotypes were divided between proximal, distal and scapuloperoneal involvement,
- genetic studies were successful in only 45% of cases with the NGS panel used,
- the genes most frequently involved were BICD2, DYNC1H1 and TRPV4,
- molecular diagnosis yields have been slightly improved by the complementary use of a panel of neuropathy genes.
As rare as they are (less than 5% of all spinal muscular atrophies), spinal muscular atrophies not linked to the SMN1 gene are far from having revealed all their secrets.
