Clinical application of long-read sequencing in newborn genetic screening for congenital adrenal hyperplasia
Peiran Zhao1, Xiaolong Qiu1, Qingying Lin1
1Medical Genetic Diagnosis and Therapy Center, Fujian Key Laboratory for Prenatal Diagnosis and Birth Defect, Fujian Maternity and Child Health Hospital College of Clinical Medicine for Obstetrics and Gynecology and Pediatrics, Fujian Medical University, Fuzhou, Fujian, China.
Background:
Screening for congenital adrenal hyperplasia (CAH) relying solely on 17α-hydroxyprogesterone (17α-OHP) presents limited diagnostic performance, highlighting an urgent need to develop more robust screening strategies for neonates.
Methods:
We conducted retrospective and prospective cohort studies to explore the clinical applicability of long-read sequencing (LRS) in CAH genetic testing within primary and secondary newborn screening (NBS) systems, respectively. The retrospective cohort comprised 100,145 neonates who underwent routine 17α-OHP primary CAH screening at the Fujian Provincial Newborn Screening Center from January 1 to December 31, 2019. Among these infants, 52 full-term screen-positive neonates received further LRS-based CAH genotyping. The prospective cohort enrolled 2,100 newborns recruited from Fujian Maternity and Child Health Hospital between May 1 and May 31, 2023, who underwent simultaneous 17α-OHP measurement and LRS-mediated CAH genetic analysis.
Results:
In the retrospective cohort, the positive rate of 17α-OHP screening was 0.19% (190/100,145, 95% CI: 0.17%-0.21%), and five infants were definitively diagnosed with CAH, corresponding to a disease prevalence of 1:20,029. LRS genotyping successfully identified five neonates harboring pathogenic CYP21A2 mutations consistent with confirmed genetic diagnosis. In this prospective cohort study, two newborns (1/1050) with normal 17α-OHP concentrations were found to carry biallelic pathogenic variants in the CYP21A2 gene. In addition, 88 neonates (4.2%) with normal 17α-OHP levels were found to carry heterozygous CAH-related variants. Among these heterozygotes, 85 individuals harbored CYP21A2 variants, representing 32 distinct genotypes. The calculated carrier frequencies were 1 in 78 for classic CAH and 1 in 40 for non-classic CAH.
Conclusion:
LRS-integrated genetic newborn screening exhibits favorable efficacy for CAH identification. This combined screening modality holds great promise for wide implementation in routine neonatal screening practice.
