SHFYNG syndrome is an autosomal dominant multisystem disorder characterized by delayed psychomotor development, impaired intellectual development, hypotonia, and behavioral abnormalities. Additional features include contractures, feeding difficulties, and variable dysmorphic facial features. The severity of the disorder is highly variable: some patients may die in utero with fetal akinesia, whereas others can live with moderate disability. Some patients may have central endocrine abnormalities, such as growth hormone deficiency or hypothyroidism. Individuals are affected only if the mutation occurs on the paternal allele, since MAGEL2 is a maternally imprinted gene. Some of the features overlap with those observed in Prader-Will syndrome (PWS; 176270) (summary by Fountain et al., 2017; Jobling et al., 2018). [from
OMIM]