Genomic imprinting disorders in the structure of syndromic obesity in children

BACKGROUND. Genomic imprinting disorders represent a distinct class of hereditary diseases caused by disruption of the monoallelic expression of imprinted genes. Several of them are closely associated with obesity and metabolic disturbances. Syndromes such as Prader–Willi, Angelman, Schaaf–Yang, Temple, and pseudohypoparathyroidism types 1a and 1b illustrate how dysregulation of imprinted gene expression can lead to energy imbalance, hyperphagia, reduced physical activity, and abnormal fat distribution. Currently, the proportion of early-onset and severe obesity cases caused by genetic factors is steadily increasing.

AIM. To study the clinical and genetic characteristics of syndromic forms of obesity in children.

MATERIALS AND METHODS. A retrospective non-comparative study. The study included 186 patients who were examined at the Endocrinology Research Center with suspected genetic forms of obesity in the period from October 2022 to May 2025.

RESULTS. Genomic imprinting disorders were confirmed in 12% of patients (n=22), including: Prader–Willi syndrome (n=12), Angelman syndrome (n=1), Schaaf–Yang syndrome (n=1), Temple syndrome (n=1), multilocus imprinting disturbances (MLID) (n=1), and pseudohypoparathyroidism type 1a (n=6). At the time of examination: 13.6% (n=3) had overweight (BMI SDS 1.0–1.9 SD), 4.6% (n=1) had grade 1 obesity (BMI SDS 2.0–2.4 SD), 18.2% (n=4) had grade 3 obesity (BMI SDS 3.0–3.9 SD), and 40.9% (n=9) had morbid obesity (BMI SDS≥4.0 SD). Excessive weight gain during the first year of life was observed in 40.9% (n=9), and in 31.8% (n=7) starting from the second year of life. Clinical signs of hyperphagia were identified in 54.5% of cases (n=12). A positive family history of obesity was identified in 31.8% of cases (n=7). The median BMI SDS was 3.71 SD [1.8025; 4.2875]. Obesity- and overweight-related complications were observed in 13 out of 17 patients.

CONCLUSION. The study presents the genetic and clinical characteristics of genomic imprinting disorders within the structure of syndromic obesity in children in the Russian Federation.

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