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Genome analyses and androgen quantification for an infant with 5α-reductase type 2 deficiency
Kazuhisa Akiba1,2, Keiko Aso3, Yukihiro Hasegawa4
1Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan.
Objectives:
5α-reductase type 2 deficiency due to biallelic SRD5A2 variants is a common form of 46,XY disorders of sex development.
Case Presentation:
A Chinese neonate presented with ambiguous genitalia. He carried a homozygous likely_pathogenic SRD5A2 variant (c.650C>A, p.A217E). His apparently nonconsanguineous parents were heterozygotes for the variant. The variant has previously been identified in two Chinese patients. Our patient carried 14.2 Mb loss-of-heterogeneity regions distributed in the genome. The SRD5A2 variant in this family was invariably coupled with two polymorphisms in exon 1 and intron 1. In the patient, blood testosterone (T)/5α-dihydrotestosterone (5αDHT) ratios were elevated before and during mini puberty, and were higher when measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) than measured by conventional immune assays.
Conclusions:
This study provides evidence for the founder effect of an SRD5A2 variant. Furthermore, our data indicate that there is a need to establish a new reference value for T/5αDHT ratios using LC-MS/MS.
