Analysis of screening results for galactocerebrosidase gene in 12 744 newborns
10.13602/j.cnki.jcls.2025.01.11
- VernacularTitle:12744例新生儿半乳糖脑苷脂酶基因筛查结果分析
- Author:
Xianwei GUAN
1
;
Yun SUN
1
;
Tao JIANG
1
;
Jingjing ZHANG
1
;
Xin WANG
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:
Krabbe disease;
GALC gene;
galactocerebrosidase;
gene screening;
carrier
- From:
Chinese Journal of Clinical Laboratory Science
2025;43(1):59-64
- CountryChina
- Language:Chinese
-
Abstract:
Objective To analyze the results of newborn screening for galactocerebrosidase(GALC)gene and enzyme activity and pro-vide a basis for the clinical diagnosis and genetic counseling of Krabbe disease.Methods The dried blood samples on filter paper from 12 744 newborns born at Nanjing Women and Children's Healthcare Hospital from March 18,2022 to December 31,2022 were collect-ed.The pathogenic variant sites of GALC gene were detected using the chip capture next-generation sequencing technology and Sanger sequencing was used for family validation.The tandem mass spectrometry was used to determine the enzyme activity of GALC in dried blood spots.The comparison of GALC enzyme activity between the carriers with GALC variants and negative group was conducted using the independent sample t-test.Results Among the 12 744 newborns,315 were identified as the carriers with GALC variants,with a carrier rate of 1/40.The most common variant was c.1901T＞C(269 cases,1/47),followed by c.1592G＞A(12 cases,1/1 062).Four newborns(P1-P4)were found to have two pathogenic variant sites and 2 cases were homozygous variants of c.1901T＞C.Family validation showed that the two variant sites in the four newborns were inherited from their parents,leading to a diagnosis of Krabbe dis-ease.Meanwhile,the family validation of the potential P2 patient's sister revealed that they had the same genotype,and the diagnosis of Krabbe disease was made.A preliminary threshold of 0.42 μmol/(L·h)for the enzyme activity of GALC detected by the tandem mass spectrometry was established based on 200 newborn samples.The GALC enzyme activities of 4 children with Krabbe disease were 0.74,0.21,0.17,and 0.29 μmol/(L·h),respectively.The GALC enzyme activity of the P2 patient's sister was 0.28 μmol/(L·h).Except for the P1 patient,the GALC enzyme activities of the P2,P3,and P4 patients and the P2 patient's sister were reduced,indica-ting a positive result.Conclusion The carrier rate of pathogenic variants in the GALC gene is relatively high,with the hotspot mutation being c.1901T＞C.The estimated prevalence of Krabbe disease is 1/3 186.The screening strategy using genetic testing as the primary screening and enzyme activity testing as the second screening can effectively improve the diagnostic efficiency of Krabbe disease,provi-ding a reference for the clinical diagnosis and genetic counseling of Krabbe disease.
