Prader-Willi syndrome

The neurobiology of the Prader-Willi phenotype of fragile X syndrome

“…Prader-Willi syndrome (PWS) is the most common cause of obesity and intellectual disability, occurring in about 1 in 15,000 in the general population (1)(2)(3). PWS is characterized by hyperphagia and lack of satiation after meals.…”

“…Behavioral and cognitive features include mild intellectual disability (ID), poor attention, obsessive behavior particularly around food so that food hoarding and food stealing are common, excessive skin picking, and remarkably good ability with puzzles. PWS is caused by an absence of expression of imprinted genes in the paternally derived PWS/Angelman syndrome (AS) region (15q11.2-q13) of chromosome 15 by one of several genetic mechanisms (paternal deletion, maternal uniparental disomy and rarely an imprinting defect) (2).…”

Insulin-driven translational capacity is impaired in primary fibroblasts of Prader Willi

“…In a patient cohort trained at our institute we observed that muscular mass did not increase after training in a normal dietary regimen (2). Muscle mass loss in PW patients has been pointed out by others (1,22) and contributes to alterations in motor performance that leads to obesity and severe disabilities. The causes of muscle weakness, and motor problems in PW patients are not clear.…”

“…Muscle hypotonia and weakness is present during the neonatal stage and in childhood. It improves with time but adults remain mildly hypotonic with a decreased muscle mass (1). As consequence, patients show an altered motor performance, abnormal gait pattern and overall a decreased physical activity that it is considered to contribute to overweight and frailty.…”

A 5-Month-Old Boy with Delay in Growth and Development and Decreased Muscle Tone

“…Physical characteristics are more evident in infancy and may include a disproportionately long head (dolichocephaly), narrow bifrontal diameter, almond-shaped eyes, thin upper lip with downturned mouth, and small hands and feet. However, the phenotype exhibits significant clinical variability with age (2 ).…”