[Familial coincidence of hypertrophic cardiomyopathies and thyroxine-binding globulin deficiency (athyropexinemia) (author's transl)].

A twenty-five year old man was found to have simultaneous total deficiency of thyroxine-binding globulin ("thyropexin") and hereditary hypertrophic obstructive cardiomyopathy (HOCM). The thyroxine-binding capacity (RT3U), thyroid hormone levels, PB127I, PB131I and TBG (RIA) in serum were very low and TBG cap was zero. Trapping of radioiodine in the thyroid was enhanced. Clinically, the patient appeared euthyroid. The case seems to be similar to another one described earlier by Ingbar. An investigation of the family showed that in one uncle and two nephews of the patient thyropexin was absent whilst the mother, one sister and one female cousin had partial thyropexin deficiencies. One of these nephews also suffers from asymmetric septal hypertrophy (ASH), the mother of the propositus has a non-obstructive hypertrophic cardiomyopathy (HCM).