Objective: To describe 10 years of experience of prenatal analysis of spinal muscular atrophy (SMA).
Methods: Data were retrospectively evaluated from prenatal analysis and carrier screening among parents and close relatives between January 2003 and December 2012. Screening was done before the parents were offered prenatal diagnosis. Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were used to detect the most frequent homozygous deletions in the SMN1 gene in fetal samples. A commercial MLPA kit (SALSA P060) was used to analyze SMN1 copy number for carrier status determination among healthy individuals. Bayesian calculation was used to accurately assess the risk of having a child affected with SMA.
Results: During the study period, 66 fetal samples from 44 Serbian families were analyzed, and 13 (19.7%) showed a homozygous deletion in the SMN1 gene. Among 28 healthy individuals, carrier status was confirmed for 16 (57.1%). For 7 couples, quantitative analyses and Bayesian calculation reduced the final risk of having a child with SMA from 1 in 200 to 1 in 2448.
Conclusion: Owing to disease severity and lack of a curative treatment, prenatal diagnosis of SMA is the best way to prevent recurrence. Carrier detection allows accurate risk assessment and appropriate genetic counseling for all family members.
Keywords: Carrier testing; Homozygous deletions; Prenatal diagnosis; SMN1; spinal muscular atrophy.
© 2013.