Phenotypic spectrum of 45,X/46,XY males with a ring Y chromosome and bilaterally descended testes.

Objective: To characterize the phenotypic spectrum of males with bilaterally descended testes and a 45,X/46,X,(r)Y karyotype.

Design: Retrospective review of patient records; cytogenetic and molecular analysis.

Setting: Tertiary medical center setting.

A mutation in the fibroblast growth factor receptor 1 gene causes fully penetrant normosmic isolated hypogonadotropic hypogonadism.

Context: Kallmann syndrome (KS) consists of idiopathic hypogonadotropic hypogonadism (IHH) and anosmia/hyposmia. Currently, the fibroblast growth factor receptor 1 (FGFR1) gene is the only known autosomal dominant cause of KS, which is also associated with synkinesia, midfacial defects, and dental agenesis.

Objective: Mutations in FGFR1 typically demonstrate reduced penetrance, variable expressivity, and until recently have been exclusively identified in families with anosmia.

The dopamine receptor D2 genotype is associated with hyperprolactinemia.

Objective: To evaluate patients with hyperprolactinemia for the presence of dopamine receptor D2 polymorphisms.

Design: Case-control study.

Setting: Academic research environment.