Silver-Russell syndrome. Observations in 20 patients.

The growth and development data of 20 patients with the Silver-Russell syndrome (14 boys, 6 girls) were analyzed. Family history, pregnancy and delivery did not reveal any significant anomalies. Birth length was 44.0 +/- 3.0 cm (boys) and 43.8 +/- 2.1 cm (girls), birth weight 2.0 +/- 0.4 kg and 2.05 +/- 0.3 kg, respectively. At the time of diagnosis (mean age 4.1 +/- 2.2 years), height was -4.4, bone age -1.9, weight -3.7, and head circumference -1.5 standard deviations below the normal mean for age. Calculated or reached adult height corresponded to 82--94% of target height. Intelligence was normal in most patients. 8 had asymmetrical extremities, 3 an asymmetrical face. 7 of 14 boys had cryptorchidism (3 uni-, 4 bilateral), 2 incomplete masculinization, and 2 of 6 girls hypertrophy of the clitoris. Development of secondary sex characters was appropriate for bone age with exception of one boy, whose puberty was early. In 3 boys with completed pubertal development, testicular volume was small and gonadotropins (before and after LHRH) high. It is concluded that 1. the growth pattern in Silver-Russell syndrome is quite homogeneous, and rather accurate predictions are possible; 2. Intersexual genitalia do not seem to be related to endocrine factors, and 3. hypergonadotropic hypogonadism appears to be frequent in males.