Background: Prader-Willi syndrome (PWS) is a complex, multisystem disorder and is the most frequent cause of syndromic obesity that arises from lack of expression of paternally inherited imprinted genes on chromosome 15q11-q13. Its major clinical features include neonatal hypotonia, short stature, developmental delay, behavioral abnormalities, hyperphagia, childhood onset obesity, hypothalamic hypogonadism, and characteristic appearance.
Case history: We report on 16 years old girl, who was referred to an endocrinologist due to amenorrhea, overweight and a short stature. Physical examination revealed: height 145.8 cm (SDS=−2.73), weight 59 kg, BMI=27.75 kg/m2 (SDS=+1.92), acromicria (short hands and feet) without facial dysmorphic features, Tanner stage 3, primary amenorrhea. When she was born, she presented neonatal muscle hypotonia, feeding problems. Her development progress was slightly delayed during the childhood and she had learning difficulties at school. The girl did not have the excessive appetite and her weight parameters were normal until 15 years. Growth retardation appeared at 14 years and at 15 - exessive weight gain. Laboratory data showed low IGF-1 level of 165.8 ng/ml (−5.8 S.D.), LG level of 0.4 IU/l, FSG 3.23 IU/l, estradiol level was 86.7 pmol/l. Gonadotrophin releasing hormone stimulation test revealed hypogonadotropic hypogonadism (LH peak 4.4 IU/l, FSH peak 11.8 IU/l). During GH provocative testing with the insulin tolerance test GH deficiency was excluded. Dual-energy x-ray absorptiometry revealed osteopenia. Diagnosis of Prader-Willi syndrome was suspected and genetically confirmed by methylation analysis of SNRPN. The girl was placed on sex hormone replacement therapy and the diet, providing 10 kcal/cm with a carbohydrate content as low as 45% of total calories and healthy balance of macronutrients, was recommended.
Discussion: Hyperphagia is the most salient and constant feature of the syndrome. Patients typically display abnormal eating behaviors including obsessive food seeking, food storage, foraging and hoarding that represent a lifelong source of distress for them and their family. However nonclassical forms of this syndrome exist, whose genetics are similar to PWS, but clinical symptomatology is not exactly typical.
27 Sep 2018 - 29 Sep 2018