Schaaf et al. (2013) reported 4 unrelated boys with Prader-Willi-like syndrome. Clinical features that met the major criteria for PWS included neonatal hypotonia with poor suck, feeding problems in infancy, hyperphagia with excessive weight gain before age 6 ... Schaaf et al. (2013) reported 4 unrelated boys with Prader-Willi-like syndrome. Clinical features that met the major criteria for PWS included neonatal hypotonia with poor suck, feeding problems in infancy, hyperphagia with excessive weight gain before age 6 years, developmental delay, and hypogonadism. Some patients had dysmorphic facial features, such as large mouth, coarse features, almond-shaped palpebral fissures, and bitemporal narrowing. More variable features in these patients that met the PWS minor criteria included short stature, small hands, narrow hands, eye abnormalities, speech defects, skin picking, and sleep apnea. Two patients had temper tantrums or violent outbursts. All had autism spectrum disorder. Two patients had contractures of the proximal and distal interphalangeal joints. Other variable features included constipation, micropenis, and cryptorchidism. One patient had seizures.
In 4 unrelated boys with Prader-Willi-like syndrome, Schaaf et al. (2013) identified 4 different de novo heterozygous truncating mutations in the MAGEL2 gene (605283.0001-605283.0004). All mutations occurred on the paternal allele. Because the maternal allele is not normally ... In 4 unrelated boys with Prader-Willi-like syndrome, Schaaf et al. (2013) identified 4 different de novo heterozygous truncating mutations in the MAGEL2 gene (605283.0001-605283.0004). All mutations occurred on the paternal allele. Because the maternal allele is not normally expressed, the findings were consistent with a loss of MAGEL2 function. The mutation in the first patient was found by clinical whole-exome sequencing. Based on these results, a research database of 1,248 whole-exome sequencing cases were reviewed, and the 3 remaining cases were identified.