A de novo deletion underlying spinal muscular atrophy: implications for carrier testing and genetic counseling.

ABSTRACT: Spinal muscular atrophy (SMA) is an autosomal recessive disease most commonly caused by homozygous deletion of the SMN1 gene. Parents of affected children are typically carriers, with a recurrence risk of 25% for future pregnancies. Their close relatives have up to 50% chance of being carriers. Carriers typically possess a single copy of the SMN1 gene; however, some parents carry two copies of SMN1. Current standard diagnostic carrier tests are unable to distinguish between silent carriers with two copies on one chromosome (2 + 0 genotype) and non-carriers (1 + 1 genotype), where a de novo deletion occurred. This distinction is crucial for recurrence risk assessment, which highlights the unsolved challenge to carrier testing and genetic counseling. We combined microsatellite marker analysi

SUBMITTER: Zwartkruis MM 

PROVIDER: S-EPMC12056310 | biostudies-literature | 2025 May

REPOSITORIES: biostudies-literature