Micropenis with testicular regression, low LH levels, and poor androgen and HCG responses: a distinct syndrome?

ABSTRACT

We report three boys, including two brothers, with micropenis and poor phallic growth in response to both exogenous human chorionic gonadotropin (HCG) and testosterone therapy in the newborn period. They exhibited low neonatal testosterone levels that failed to respond to HCG stimulation. These boys displayed a unique gonadotropin profile with reduced luteinizing hormone levels and elevated follicle-stimulating hormone levels. They had small, cryptorchid testes with subsequent testicular regression and atrophy. Moreover, all three boys have developed microcephaly and mild learning delays. We review the hormonal profiles and phenotypes of known causes of micropenis, and compare them to the features of our three patients. Although individuals with similar features may have been described in past series of males with micropenis, the data presented previously were insufficient for classification; thus, we propose that our patients may represent a distinct, not previously recognized, syndrome with either X-linked recessive inheritance or autosomal recessive inheritance with male sex limitation.