Spinal muscular atrophy carrier frequency in Saudi Arabia.

Area of Science:

• Genetics
• Neurology
• Public Health

Background:

• Spinal Muscular Dystrophy (SMA) is a leading heritable disease affecting infants and children.
• Saudi Arabia has a higher reported incidence of SMA, potentially linked to consanguineous marriage practices.

Purpose of the Study:

• To determine the carrier frequency and estimate the prevalence of Spinal Muscular Dystrophy (SMA) in the Saudi population.
• To investigate the correlation between consanguinity and SMA incidence in Saudi Arabia.

Main Methods:

• Genomic DNA was isolated from whole blood samples of 4198 healthy volunteers (18-25 years old).
• SMN1 gene copy number was determined using Multiplex PCR with Dral restriction fragment analysis.
• Carrier frequency and population data were used with the life-table method to estimate SMA prevalence.

Main Results:

• The carrier frequency for SMA in Saudi Arabia was found to be 2.6% (1 in 38 individuals).
• Females exhibited a higher carrier frequency (3.7%) compared to males (1.6%).
• The estimated birth incidence of SMA is 32 per 100,000 births, with an estimated 2265 individuals living with SMA in Saudi Arabia.

Conclusions:

• The SMA carrier rate in Saudi Arabia (2.6%) is higher than the global average (1.25-2%).
• High consanguinity rates in the Saudi population are strongly associated with the elevated SMA carrier frequency.