WHAT'S KNOWN ON THIS SUBJECT:Standardized growth curves do not exist for infants with Prader-Willi syndrome. Syndromespecific growth charts are required for monitoring growth and nutritional status, particularly during growth hormone treatment and follow-up for this disorder during infancy. WHAT THIS STUDY ADDS:Standardized growth curves are reported to be used in monitoring growth and development of infants with Prader-Willi syndrome of both genders from 0 to 36 months of age. abstract OBJECTIVE: To generate and report standardized growth curves for weight, length, head circumference, weight/length, and BMI for nongrowth hormone-treated white infants (boys and girls) with PraderWilli syndrome (PWS) between 0 and 36 months of age. The goal was to monitor growth and compare data with other infants with PWS. METHODS:Anthropometric measures (N ϭ 758) were obtained according to standard methods and analyzed from 186 non-growth hormone-treated white infants (108 boys and 78 girls) with PWS between 0 and 36 months of age. Standardized growth curves were developed and the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles were calculated by using the LMS (refers to , , and ) smoothing procedure method for weight, length, head circumference, weight/ length, and BMI along with the normative 50th percentile using Centers for Disease Control and Prevention national growth data from 2003. The data were plotted for comparison purposes. RESULTS:Five separate standardized growth curves (weight, length, head circumference, weight/length, and BMI) representing 7 percentile ranges were developed from 186 non-growth hormone-treated white male and female infants with PWS aged 0 to 36 months, and the normative 50th percentile was plotted on each standardized infant growth curve. CONCLUSIONS:We encourage the use of these growth standards when examining infants with PWS and evaluating growth for comparison purposes, monitoring for growth patterns, nutritional assessment, and recording responses to growth hormone therapy, commonly used in infants and children with PWS.

Background Prader-Willi syndrome (PWS) is a complex genetic disorder with errors in genomic imprinting, generally due to a paternal deletion of chromosome 15q11-q13 region. Maternal disomy 15 (both 15s from the mother) is the second most common form of PWS resulting from a trisomic zygote followed by trisomy rescue in early pregnancy and loss of the paternal chromosome 15. However, trisomy 15 or mosaicism for trisomy 15 may be present in the placenta possibly leading to placental abnormalities affecting gestational age and delivery. Methods and Subjects We examined growth and gestational data from 167 PWS infants (93 males and 74 females; 105 infants with 15q11-q13 deletion and 62 infants with maternal disomy 15) to determine if there are differences in gestation between the two genetic subtypes. Results No significant differences in growth data (birth weight, length, head circumference) or average gestational ages were found between the two genetic subgroups.