Carrier frequency of spinal muscular atrophy in Turkish population

Abstract

Objective: The aim of this retrospective cohort study is to evaluate the carrier frequency of spinal muscular atrophy (SMA) among pregnant women and their partners admitted to our clinic for routine pregnancy follow-up. Methods: The study included pregnant women and their partners who were informed about SMA disease and screening at first trimester and who accepted to undergo screening for SMA. Carrier screening for SMA was carried out using DNA extracted from peripheral blood with a quantitative real-time polymerase chain reaction (qPCR) assay targeting the recurrent SMN1 exon 7-8 gene deletion. The data of the study were analyzed by SPPS version 15.0 statistical software package. Descriptive statistical analyses were carried out. Fisher’s exact test was used for intergroup comparisons. Results: The study included a total of 250 subjects, of whom 182 were female and 68 were male. The carrier frequency of SMN1 deletion was 3.6% (9/250) (95% CI: 1.66–5.54) in the entire study population, with a carrier frequency of SMN1 deletion of 1/27.8. Of 182 female participants, 6 had SMN1 deletion, with a carrier frequency of SMN1 deletion of 3.3% (95% CI: 1.3–6.2). Of 68 male participants, 3 had SMN1 deletion, with a carrier frequency of SMN1 deletion of 4.4% (95% CI: 0.35–9.4). There was no significant difference between female and male participants in terms of SMN 1 deletion frequencies (p=0.712). SMN1 duplication frequency was 8% (95% CI: 5.18–10.8) in all gender. Conclusion: The results of this study demonstrated a carrier frequency of SMN1 deletion of 1/27.7 in the Turkish population, which is higher than in many other countries. The results of the study will be useful for genetic counseling for SMA.