To determine the carrier rate of spinal muscular atrophy (SMA) among women of reproductive age in the Shaoguan, Guangdong Province, and to provide prenatal diagnosis for couples where both partners are identified carriers, aiming to prevent the birth of SMA-affected infants.

A total of 2646 pregnant women were screened using fluorescent quantitative PCR technology to detect the copy number of exons 7 and 8 (E7, E8) of the survival motor neuron gene 1 (SMN1). Prenatal diagnosis was conducted for high-risk couples who were both SMA carriers, and the fetal genotype results were verified using multiplex ligation-dependent probe amplification (MLPA).

Among the 2646 pregnant women, 54 SMA carriers were identified, yielding a carrier rate of 2.04% (54/2646). The carrier genotypes were categorized as follows: 41 cases had concurrent heterozygous deletions of SMN1 gene E7 and E8, 1 case had an isolated heterozygous E7 deletion, and 12 cases had an isolated heterozygous E8 deletion. Prenatal diagnosis was performed for two couples who were both partners carried a heterozygous SMN1-E7 deletion. The results identified one fetus with a heterozygous deletion of SMN1-E7 and E8 and one fetus with a normal genotype. These findings were consistent with the MLPA verification.

The carrier rate of SMA mutations in the pregnant population is relatively high in Shaoguan region of Guangdong. It is necessary to conduct SMA carrier screening among pregnant women and to perform invasive prenatal genetic diagnosis for high-risk fetuses whose parents are both SMA carriers. This approach is of great significance for effectively preventing the birth of SMA-affected infants and reducing the incidence of birth defects.