2+0 deletion carrier - a limitation of the genetic testing and counseling: A case report.

Background: gene mutations may all cause reduction or loss of 21-hydroxylase activity, leading to development of congenital adrenal hyperplasia (CAH) with different clinical phenotypes. For families with CAH children, genetic testing of the parents and genetic counseling are recommended to assess the risk of recurrence.

Case Summary: We report a case of CAH with a high suspicion before delivery. The risk of the child suffering from CAH during the pregnancy had been underestimated due to the deviation of genetic counseling and genetic testing results. Our report confirmed a homozygous deletion in this case, heterozygous deletion in the mother, and a rare 2+0 deletion in the father.

Conclusion: It is important to analyze the distribution of gene in the two alleles of parents of children with CAH.