Patients with acromegaly come from tall families

The heights of 59 patients with acromegaly and their first-degree relatives were studied. The mean height SD score (SDS) for the patients was 0.93 +/- 1.19 (equivalent to 5.6 cm above the population mean), and for their siblings (N = 166) 0.39 +/- 1.05 (2.3 cm above the population mean) (P less than 10-5 for difference from the general population). The height distribution of both groups was markedly positively skewed. Probably the parents were as tall (in relation to the population of their age) as the siblings. Growth data were available for 13 of the patients and showed that the height of the tall (SDS greater than 2.0) patients had increased by 2.5-10 (mean 5) cm after normal cessation of growth. This explains the extra height of the patients over their siblings. Only 2 of the 13 patients became oversized for their families during the normal growth period. We suggest that in a part of the population with acromegaly the disease is associated with primary genetic tallness.