Familial growth hormone deficiency associated with MRI abnormalities.

Idiopathic growth hormone deficiency is, in most cases, a sporadic condition. In a number of these patients magnetic resonance imaging (MRI) demonstrates a small anterior pituitary, small or absent pituitary stalk, and ectopically located posterior pituitary. These findings have been attributed to a developmental defect, trauma, or ischemia at birth. We report on a case of familial isolated growth hormone deficiency with mother and son demonstrating the MRI findings described above. The son also had a Chiari type I malformation and medial deviation of the carotid arteries secondary to a narrow skull base. Testing failed to identify a mutation in either the Pit-1 gene or GH gene cluster. This case appears to be an autosomal dominant defect in early development, lending support to the hypothesis that dysgenesis, rather than birth trauma, may cause a small anterior pituitary and ectopic posterior pituitary.