46,XY differences of sex development in pontocerebellar hypoplasia type 7 (PCH7): two case reports and systematic review.

OBJECTIVES

We report two cases of 46,XY siblings with pontocerebellar hypoplasia type 7 (PCH7) and conduct a systematic literature review for genetically confirmed PCH7 cases, focusing on phenotypic characteristics, particularly gonadal parameters, and associated genotypic data.

CASE PRESENTATION: Two 46,XY siblings diagnosed with PCH7 were reviewed. Both exhibited hypoplastic male external genitalia, absent uterus, and cryptorchid testes, confirmed through histological assessments showing dysgenesis. A systematic literature search revealed an additional 26 cases of 46,XY PCH7, with neurological involvement noted in all cases except one. The external genitalia were described as abnormal (17/23); however, few of these were hypoplastic male type on pictorial review. Nonlocalized testes (5/5) and absent uterus (4/7) on ultrasonography, elevated FSH (7/7), and low testosterone (3/3) were observed. Besides a novel variant (p.Ile133Thr) in Indian siblings, a total of 25 variants in TOE1 were identified with no specific genotype-phenotype correlation.

CONCLUSIONS

Testicular development was defective in all PCH7 patients but was variable, with the predominant phenotypic manifestation being testicular regression syndrome/partial gonadal dysgenesis with Müllerian duct regression (TRS/PGD-MDR).