Birth seasonality in Korean Prader-Willi syndrome with chromosome 15 microdeletion

PURPOSE: Prader-Willi syndrome (PWS) is a well-known genetic disorder, and microdeletion on chromosome 15 is the most common causal mechanism. Several previous studies have suggested that various environmental factors might be related to the pathogenesis of microdeletion in PWS. In this study, we investigated birth seasonality in Korean PWS. METHODS: A total of 211 PWS patients born from 1980 to 2014 were diagnosed by methylation polymerase chain reaction at Samsung Medical Center. Of the 211 patients, 138 were born from 2000-2013. Among them, the 74 patients of a deletion group and the 22 patients of a maternal uniparental disomy (UPD) group were compared with general populations born from 2000 using the Walter and Elwood method and cosinor analysis. RESULTS: There was no statistical significance in seasonal variation in births of the total 211 patients with PWS (chi2=7.2522, P=0.2982). However, a significant difference was found in the monthly variation between PWS with the deletion group and the at-risk general population (P<0.05). In the cosinor model, the peak month of birth for PWS patients in the deletion group was January, while the nadir occurred in July, with statistical significance (amplitude=0.23, phase=1.2, low point=7.2). The UPD group showed the peak birth month in spring; however, this result was not statistically significant (chi2=3.39, P=0.1836). CONCLUSION: Correlation with birth seasonality was identified in a deletion group of Korean PWS patients. Further studies are required to identify the mechanism related to seasonal effects of environmental factors on microdeletion on chromosome 15.

Does Type I Truly Dominate Hepatic Glycogen Storage Diseases in Korea?: A Single Center Study / 대한소아소화기영양학회지

PURPOSE: There are no studies of hepatic glycogen storage diseases (GSDs) other than type I and III in Korea. We aimed on investigating the characteristics of hepatic GSDs in Korea diagnosed and followed at a single center. METHODS: We retrospectively analyzed patients who were diagnosed as GSD and followed at Samsung Medical Center from January, 1997 to December, 2013. Clinical manifestations, laboratory results, treatment, and prognosis were investigated. RESULTS: Twenty-one patients were included in the study. The types of 17 patients were confirmed by enzyme activity tests and/or gene analysis. GSD Ia was diagnosed in 7 patients (33.3%), Ib in 1 patient (4.8%), III in 2 patients (9.5%), IV in 1 patient (4.8%), and IX in 6 patients (28.6%). Types other than GSD I constituted 52.9% (9/17) of the patients diagnosed with a specific type of hepatic GSD. The median age at presentation was 2 years. Hepatomegaly was observed in 95.2%, elevated liver transaminases in 90.5%, and hyperlactacidemia in 81.0% of the patients. The duration for follow-up was 77+/-62.0 months. Uncooked corn starch was initiated in all the patients. No mortality was observed during the follow-up period, and liver transplantation was performed in 14.3%. CONCLUSION: Types other than GSD I comprised more than half of the patients diagnosed with a specific type of hepatic GSD. Clinical suspicion and thorough evaluation of hepatic GSDs in Korea should be focused not only on GSD I, but also on other types.