Growth and developmental patterns in Prader‐Willi syndrome

Eleven Japanese patients with Prader-Willi syndrome were studied from infancy, and examined with respect to their growth and development. The chromosomal aberration was observed in 40% of the patients using a high-resolution chromosome banding technique. The birth weight in 10 out of the 11 patients was below the mean and the rate of body weight gain was severely retarded by 6 months in all cases, which suggested an insufficient utilization of nutrients in uterine life and in early infancy. The rate of height increase as well as that of body weight increase were also transiently retarded from 10 to 18 months of age in eight cases, and the body weight gain increased dramatically after 10-18 months due to hyperphagia. The patients' mean milestones of development were delayed (the mean developmental quotient was 50) in comparison with those of control patients; there was no difference between the developmental milestones of the two groups with and without the chromosomal aberration.