RESUMO
Hypomyelination with hypogonadotropic hypogonadism and hypodontia (4H syndrome) is a rare disease, characterized by both central and peripheral hypomyelination. We describe a 21-year-old male with mildly progressive ataxia, mental retardation, pituitary hypogonadotropic hypogonadism, delayed dentition, and cataract. Brain magnetic resonance imaging showed hypomyelinated white matter, cerebellar atrophy, and a thin corpus callosum. The literature suggests that abnormal findings upon sural nerve biopsy may indicate peripheral hypomyelination, even in the absence of clinically and physiologically evident peripheral neuropathy. A sural nerve biopsy of this patient was normal, and this finding is further discussed. Taken together with previous reports, this case suggests that 4H syndrome can be regarded as a spectrum disorder, the cardinal signs of which may be central hypomyelination, ataxia, hypogonadotropic hypogonadism, and hypodontia.