Dysmorphology and clinical genetics : official publication of the Center for Birth Defects Information Services, Inc最新文献

Due to the lack of normative data in newborns, we report fat and muscle patterning, and standards for the sums of fat and muscle areas and muscle circumferences for arm, forearm, thigh, and calf in white and black newborn infants that may have clinical application in the assessment of body composition in newborns. Significant differences were found between white males and white females in fatness patterning: white female newborns were larger for all 21 variables except height. Statistically significant differences (t test; p < 0.05) existed for five skinfold measurements (forearm, subscapular, suprailiac, thigh, medial calf), three limb fat areas (forearm, thigh, calf), and the sums of the skinfolds and fat areas despite similar limb circumferences. Black female newborns were larger than black males for five of the eight skinfolds (with a significant difference observed in medial calf skinfold), for all of the limb fat areas, and for the sums of the skinfolds and fat areas. Despite their larger skinfolds and fat areas, black females had smaller circumferences. No sex-related trends or significantly different variables were observed in the muscle patterning of white infants. Differences in muscle patterning were observed between black males and black females, with males having larger values for all 14 variables. Statistically significant differences were found between white and black infants, with white newborns having greater height, medial calf skinfold, and calf fat area.

To determine the effects of familial background on anthropometric dimensions in Prader-Willi syndrome (PWS), we measured weight; height; sitting height; longitude and breadth of the head, hands, and feet; head, arm, and calf circumferences; and triceps and subscapular skinfolds in 28 individuals with the syndrome and their natural parents. Midparental-child correlations were significant for height and foot length, with heritability estimates of 0.52 and 0.68, respectively. Significant mother-child correlations were found for weight, height, foot length, and minimal frontal diameter for the total group; in addition, hand length and breadth, and calf and arm circumferences were significant for the patients age 12.5 years or under. These data provide evidence for maternal effects on several physical characteristics in PWS, particularly in younger patients.

Prader-Willi syndrome (PWS) may represent a genetic form of human obesity. The purpose of this study was to determine whether the relationship between resting metabolic rate and body weight/body composition was different in patients with PWS than in obese (body mass index 23-36) and lean (body mass index 15-20) controls. We determined body composition using bioelectrical impedance analysis (BIA) and skinfold thickness measurements in 36 subjects with PWS and in 31 controls (20 nonobese, 11 obese). The BIA measures of percentage of body fat were significantly correlated with those determined from skinfold thicknesses in all three groups. Resting metabolic rate (RMR) was measured in all lean and obese controls and in 22 of the 36 patients. Energy expenditure was compared among groups by comparing the regression relationship between RMR and either body weight or fat-free mass (FFM). The relationship between RMR and body weight and between RMR and FFM was different for patients with PWS than for lean and obese controls, who did not differ from each other. The nature of the relationship was such that patients with PWS had reduced rates of energy expenditure compared to controls, except for patients with the largest body mass and FFM. This suggests that a low energy expenditure exists initially for persons with PWS but may return to normal as obesity becomes greater. These results also suggest that reduced FFM is not the sole explanation for the lower energy expenditure seen in patients with PWS.

To determine if certain features (e.g., hypopigmentation) seen in persons with Prader-Willi syndrome (PWS) may be reflected in abnormalities of amino acid metabolism, fasting plasma amino acid levels were measured from 25 patients and compared with those in 17 obese individuals. Thirteen of the patients with PWS were previously identified by high-resolution analysis to have chromosome 15q deletion, while 12 had normal chromosomes. Compared with reference plasma levels, several amino acid levels were elevated in both patients and obese individuals. Aspartic acid, taurine, and glutamic acid levels were elevated (>2 Z score) in 44% of the patients with PWS but were increased in only one obese individual. The average phenylalanine and tyrosine levels were not different in the two groups. Significant differences in taurine, cystine, glutamic acid, citrulline, and aspartic acid levels were found. There was no correlation with age, degree of obesity (percentage of ideal body weight), and the degree of elevation of amino acids in either patients with PWS or obese individuals. Similarly, the degree of obesity in those with PWS was not associated with chromosome status. Several amino acid concentrations were abnormal in patients compared with our laboratory reference ranges, but many of these abnormalities were also present in obese individuals. Whether the amino acid changes simply reflect the altered eating habits of obese individuals or whether the altered profile may play a role in appetite or energy regulation is not known.

Plasma lipid, glucose, and insulin levels were measured from 26 patients with Prader-Willi syndrome (16 with the chromosome 15q deletion and 10 with normal chromosomes) and 32 obese, normal individuals. The average percentage of ideal body weight (IBW) for the former group was 175.6 ± 68.0, compared to 150.3 ± 43.8 for the latter. Fasting plasma lipid, glucose, and insulin levels were not significantly different between the two groups. No significant correlations were found among the three measurements in patients with PWS (deletion or nondeletion) or obese individuals and either age or percentage of IBW. Both insulin and glucose levels were higher in the PWS group, while only insulin levels were higher in the obese group compared with normative laboratory standards. Our study supports previously reported lipid, glucose, and insulin data in PWS and obesity.