Comprehensive Overview of Congenital Adrenal Hyperplasia and its Genetic Diagnosis Among Children and Adolescents

Abstract

The most common cause for congenital adrenal hyperplasia (CAH) is 21-hydroxylase deficiency (21OHD). This enzyme is encoded by the CYP21A2 gene which is highly homologous to its pseudogene CYP21A1P complicating the genetic analysis. We propose an algorithmic approach to genetic testing in 21OHD CAH utilizing multiple molecular techniques such as allele-specific polymerase chain reaction (ASPCR) and targeted gene sequencing to make it cost-effective. We recommend the classification of the common genetic mutations as Null and A–D, as established on functional enzyme studies. Pediatricians and pediatric endocrinologists need to be aware of the excellent genotypephenotype correlations established in the severe salt wasting CAH as highlighted in this review.