[Analysis of differences in clinical and biochemical characteristics and treatment effects in patients with different genotypes of Prader-Willi syndrome].

Objective: To analyze the differences in clinical and biochemical characteristics and treatment effects in patients with different genotypes of Prader-Willi syndrome (PWS). Methods: A total of 35 patients with PWS, 20 males and 15 females aged from 0.8 to 10.0 years with an average age of 3.0 years, were retrospectively included in this study. All of them were treated in the Department of Endocrinology of Peking Union Medical College Hospital from May 2017 to December 2018. The clinical material, biochemical data, and peripheral blood samples of the patients were collected. Genomic DNA was extracted from peripheral blood leukocytes of patients, and methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) was used to detect gene deletion or abnormal methylation. According to the results of detection, 35 patients were divided into two groups: paternal deletion group(n=27) and methylation abnormal group(n=8). The biochemical test results and the effect of growth hormone (GH) treatment of the two groups were analyzed. Results: MS-MLPA showed that 77% (27/35) of the patients were confirmed paternal deletion and 23% (8/35) were abnormal methylation. In terms of biochemical test results, the plasma concentrations of uric acid(UA) in the paternal deletion group were higher than that in the abnormal methylation group [(363±101) μmol/L vs (259±74) μ mol/L, P=0.019 ]. There is a linear relationship between body weight and uric acid level. After adjustment for weight., there was no significant difference in UA level between the two groups (P=0.101). Patients in both groups were treated with GH ((0.14±0.03) U/kg, QD). In paternal deletion group, patients were followed up for (26.0±13.6) months, and their height increased from (99.0±31.5) cm [(-0.3±1.1) SDS] to (107.5±27.0) cm [(0.7±0.9) SDS] (P=0.037). In the abnormal methylation group, patients were followed up for (25.8±11.6) months, and their height increased from (86.4±31.2) cm [(-0.7±1.8) SDS] to (95.6±26.5) cm [(0.0±1.6) SDS] (P=0.557). There was no significant difference in body mass index (BMI) between paternal deletion group and abnormal methylation group before and after treatment [(22.0±7.1) vs (22.4±6.8)] kg/m2, P=0.890;(17.0±3.1) vs (16.4±2.7) kg/m2, P=0.754]. Conclusions: There were no significant differences in biochemical test results between patients with paternal deletion and those with abnormal methylation. Early treatment with GH in PWS patients can effectively improve the increasing height and reduce excessive weight gain.