The acid-stable subunit of the GH-dependent large mol wt somatomedin-binding protein (SmBP) was isolated from human plasma Cohn fraction IV by a three-step procedure, and a specific RIA was developed which allowed measurement in unextracted serum. Although in normal human serum most of immunoreactive material was present as the large mol wt complex (150K), considerable amounts of smaller components were found by high performance liquid exclusion chromatography in the 60K, 42K, and 32K range. Normal serum levels were low at birth, rose sharply during the first weeks of life, and showed a moderate peak at puberty. To assess the diagnostic efficacy of SmBP for GH deficiency (GHD), patients previously diagnosed as GH-deficient by conventional criteria (n = 132) were compared to short statured children without GHD (n = 130). Taking the fifth centile as a limit of normality the majority of patients with GHD had subnormal levels, yielding high sensitivity of the test (0.97). In contrast, most of the non-GH-deficient children had SmBP levels within the normal range, resulting in high specificity (0.95) and, consequently, high accuracy (0.96). These results suggest that the large mol wt SmBP is an excellent screening parameter and is highly informative for GHD.

The spontaneous growth of 150 patients with Turner syndrome from three German centers--90 with 45,X0 constitution, 60 with other chromosomal abnormalities--has been analyzed. The mean adult height was found to be (n = 14) 146.8 cm. It was observed that growth in these patients can be divided into four phases: (1) Intrauterine growth, which is retarded; (2) Height development, which is normal up to a bone-age of about 2 years; (3) Between a bone-age of 2 and 11 years when stunting of growth is most marked; (4) After a bone-age of 11 years--the time at which puberty should normally start--the growth phase is prolonged, but total height gain is only little below normal levels. No difference in height could be observed between cases with X0 karyotype and other chromosomal variants. The data are compared with those in the literature.

We have analysed growth and the major clinical manifestations of 144 patients (89 males, 55 females) with Noonan syndrome from two West German centres. Size at birth was normal in both sexes. In both males and females, the mean height followed along the 3rd per centile until puberty, but decreased transiently due to an approximately 2 year delay in onset of puberty. Final height approaches the lower limits of normal at the end of the 2nd decade of life. The mean adult height was found to be (n = 20) 162.5 cm in males and (n = 13) 152.7 cm in females, respectively. Smoothed means and standard deviations for height were derived. These data may be used for the statistical evaluation of height of Noonan syndrome patients. Except for mental retardation and microcephaly, which are more frequent in males, the relative frequencies of minor anomalies and malformations were found to be similar in both sexes. The characteristic non-cyanotic heart defects in the Noonan syndrome do not appear to have a major influence on growth. The auxological data were compared with those in the Ullrich-Turner syndrome.