Prevalence of pathogenic variants carrier of acid alpha-glucosidase gene among newborns in Nanjing
10.3760/cma.j.cn113903-20241128-00793
- VernacularTitle:南京地区新生儿酸性α-葡萄糖苷酶基因致病性变异的携带情况
- Author:
Zhilei ZHANG
1
;
Yun SUN
1
;
Xin WANG
1
;
Xianwei GUAN
1
;
Tao JIANG
1
;
Zhengfeng XU
1
Author Information
1. 南京医科大学附属妇产医院（南京市妇幼保健院）遗传医学中心，南京 210004
- Publication Type:Journal Article
- Keywords:
Pompe disease;
GAA gene;
Genetic screening;
Carrier
- From:
Chinese Journal of Perinatal Medicine
2025;28(5):371-380
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To assess the prevalence of pathogenic variants in the acid alpha-glucosidase ( GAA) gene among newborns in Nanjing and provide a reference for early screening, diagnosis, and treatment of Pompe disease. Methods:This retrospective study conducted on 30 043 live births at Women's Hospital of Nanjing Medical University (Nanjing Women and Children's Healthcare Hospital) from March 2022 to October 2024. Heel blood samples were collected within 48 h after birth to make dried blood spots. Chip-capture-based next-generation sequencing was used to detect pathogenic/likely pathogenic (P/LP) GAA variants. Suspected cases underwent Sanger sequencing validation and GAA enzyme activity assay to summarize the carrier status of pathogenic variants in the GAA gene among newborns. Descriptive statistical analysis was used. Results:Among the 30 043 newborns, 232 carriers (one P/LP variant) and four presumptive cases (two P/LP variants) were identified. The GAA activity of suspected cases 1 and 2 was normal, and the two variants were in cis, leading to a clinical diagnosis of carriers. Presumptive case 3 had a GAA activity of 0.17 μmol/(L·h), below the normal range [2.63-21.69 μmol/(L·h)]; the two variants were in trans, without clinical manifestations of Pompe disease follow-up to 2 years and 1 month, resulting in a clinical diagnosis of a potential patient. Presumptive case 4 had a GAA activity of 0.36 μmol/(L·h), below the normal range; the two variants were in cis, and two pseudodeficiency variants [c.1726G>A(p.G576S) and c.2065G>A(p.E689K)] were also found, leading to a final clinical diagnosis of a carrier. Therefore, a total of 235 carriers of P/LP GAA variants were identified, with a carrying rate of 1/128 (235/30 043), and one potential patient was identified with an incidence rate of 1/30 043. The top five common GAA variants were c.2132_2133delinsGG, c.503G>A, c.-32-13T>G, c.2662G>T, and c.2238G>C, with allele frequencies of 0.078% (47/60 086), 0.038% (23/60 086), 0.020% (12/60 086), 0.018% (11/60 086), and 0.017% (10/60 086), respectively. Protein structure prediction results showed that c.2132_2133delinsGG resulted in a shortened two β-sheet in GH31(β/α) 8 barrel catalytic domain and altered signal peptide and prepeptide conformation. c.503G>A would extend one β-sheet and add an additional β-sheet in the N-terminal domain. Conclusion:Newborn genetic screening combined with GAA activity measurement can exclude the interference of pseudodeficiency alleles, improve screening efficiency and accuracy, and provide a reference for the clinical diagnosis and genetic counseling of Pompe disease.
