Prenatal genetic counseling challenges with indeterminate SMA results.

ABSTRACT: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular condition with complex genetic etiology. About 95% of individuals affected with this condition have a homozygous deletion of the SMN1 gene. One scenario that complicates risk is when a parent is identified as a possible silent carrier, meaning they have a [2 + 0] chromosome configuration. This configuration occurs when an individual has two copies of the SMN1 gene on one chromosome and no copies on the other chromosome. It is thought that 3.8-4.0% of the general population is a [2 + 0] carrier with a higher prevalence in African American and Hispanic populations. The [2 + 0] configuration makes it more difficult to calculate residual risk because testing cannot determine the difference between [2 + 0] carriers and [1 + 1

SUBMITTER: Spangenberg M 

PROVIDER: S-EPMC11965976 | biostudies-literature | 2025 Apr

REPOSITORIES: biostudies-literature