Spinal muscular atrophy carrier frequency in Saudi Arabia

• Published in: Molecular genetics & genomic medicine Vol. 10; no. 11; pp. e2049 - n/a
• Main Authors: Al Jumah, Mohammed, Al Rajeh, Saad, Eyaid, Wafaa, Al‐Jedai, Ahmed, Al Mudaiheem, Hajar, Al Shehri, Ali, Hussein, Mohammed, Al Abdulkareem, Ibrahim
• Format: Journal Article
• Language: English
• Published: United States John Wiley & Sons, Inc 01.11.2022; John Wiley and Sons Inc; Wiley
• Subjects: Adolescent; Adult; Age; Atrophy; Births; Carrier frequencies; Child; Child, Preschool; Children; Chromosomes; consanguineous marriages; Consanguinity; Copy number; Data analysis; Dystrophy; epidemiology; Family; Family medical history; Female; Females; Genes; Genetics; Genomes; Genotype & phenotype; Humans; Infant; Life expectancy; Male; Males; mass screening; Medical screening; Multiplex Polymerase Chain Reaction - methods; Muscular Atrophy, Spinal - epidemiology; Muscular Atrophy, Spinal - genetics; Muscular dystrophy; Mutation; Original; Saudi Arabia; Saudi Arabia - epidemiology; SMN protein; Spinal muscular atrophy; Young Adult; Saudi Arabia; Saudi Arabia; epidemiology; mass screening; spinal muscular atrophy; consanguineous marriages
• ISSN: 2324-9269; 2324-9269
• DOI: 10.1002/mgg3.2049

Background Spinal Muscular Dystrophy (SMA) is one of the leading causes of death in infants and young children from heritable diseases. Although no large‐scale popultion‐based studies have been done in Saudi Arabia, it is reported that the incidence of SMA is higher in the Saudi population partly because of the high degree of consanguineous marriages. Methods The final analysis included 4198 normal volunteers aged between 18 and 25 years old, 54.7% males, and 45.3% females. Whole blood was spotted directly from finger pricks onto IsoCode StixTM and genomic DNA was isolated using one triangle from the machine. To discern the SMN1 copy number independently from SMN2, Multiplex PCR with Dral restriction fragment analysis was completed. We used the carrier frequency and population‐level data to estimate the prevalence of SMA in the population using the life‐table method. Results This data analysis showed the presence of one copy of the SMN1 gene in 108 samples and two copies in 4090 samples, which resulted from a carrier frequency of 2.6%. The carrier frequency was twofold in females reaching 3.7% compared to 1.6% in males. 27% of participants were children of first‐cousin marriages. We estimated the birth incidence of SMA to be 32 per 100,000 birth and the total number of people living with SMA in the Kingdom of Saudi Arabia to be 2265 of which 188 are type I, 1213 are type II, and 8,64 are type III. Conclusion The SMA carrier rate of 2.6% in Saudi control subjects is slightly higher than the reported global frequency of 1.25 to 2% with links to the high degree of consanguinity. The birth incidence of SMA was estimated to be 32 per 100,000 birth and the total number of people living with SMA in KSA to be 2265 of which 188 are type I, 1213 are type II, and 864 are type III. The SMA carrier rate of 2.6% in Saudi subjects is slightly higher than the reported global frequency with links to the consanguineous marriages.