Genotype-phenotype correlation and founder effect analysis in southeast Chinese patients with sialidosis type I.

Background: Sialidosis type 1 (ST-1) is a rare autosomal recessive disorder caused by mutation in the NEU1 gene. However, limited reports on ST-1 patients in the Chinese mainland are available.

Methods: This study reported the genetic and clinical characteristics of 10 ST-1 patients from southeastern China. A haplotype analysis was performed using 21 single nucleotide polymorphism (SNP) markers of 500 kb flanking the recurrent c.544 A > G in 8 families harboring the mutation. Furthermore, this study summarized and compared previously reported ST-1 patients from Taiwan and mainland China.

Results: Five mutations within NEU1 were found, including two novel ones c.557 A > G and c.799 C > T. The c.544 A > G mutation was most frequent and identified in 9 patients, 6 patients were homozygous for c.544 A > G. Haplotype analysis revealed a shared haplotype surrounding c.544 A > G was identified, suggesting a founder effect presenting in southeast Chinese population. Through detailed assessment, 52 ST-1 patients from 45 families from Taiwan and mainland China were included. Homozygous c.544 A > G was the most common genotype and found in 42.2% of the families, followed by the c.544 A > G/c.239 C > T compound genotype, which was observed in 22.2% of the families. ST-1 patients with the homozygous c.544 A > G mutation developed the disease at a later age and had a lower incidence of cherry-red spots significantly.

Conclusion: The results contribute to gaps in the clinical and genetic features of ST-1 patients in southeastern mainland China and provide a deeper understanding of this disease to reduce misdiagnosis.