Endocrine Abstracts

Introduction: Prader-Willi syndrome (PWS) is a neurobehavioral imprinting disorder, which arises due to an absence of paternally expressed genes within the 15q11.2-q13 region. It is the most common syndromic form of obesity, with an estimated prevalence of about 1 in 25,000 individuals.

Case report: we report the case of two monozygotic twins, 20-year-old, naturally conceived, both affected by PWS. They were born by eutocic delivery at 34 weeks of gestation and somatometry was appropriate for gestational age. Both presented neonatal hypotony, feeding difficulties, psychomotor delay, characteristic facies and cryptorchidism. Genetic test confirmed maternal uniparental disomy of chromosome 15. From 4 years of age they presented progressive increasing weight (percentile > 95) associated with binge-eating but delayed height growth (percentile 10-25). Orchidopexy was performed at 5 years of age. Puberty started at 12 years but did not progress. At 16-year-old, treatment with testosterone enanthate monthly injections and recombinant human growth hormone (rhGH) was started. Despite dietetic measures, both twins developed insulin resistance and morbid obesity (body mass index: 49.8 and 44 kg/m²) due to marked hyperphagia. Furthermore, they had obstructive sleep apnea, cognitive delay and behavioral problems (temper tantrums, stubbornness, impulsivity, aggressiveness), which ultimately led to the cessation of treatment with testosterone. Worsening of obesity and sleep apnea at the age of 19 dictated the stop of rhGH.

Conclusion: To our knowledge, very few cases of naturally conceived twins affected with PWS were reported. Endocrine treatments can be controversial in these patients, because of a possible exacerbation of behavioral problems and other comorbid conditions.