Intellectual Developmental Disorder, Autosomal Dominant 42, also known as mrd42, is related to contractures, pterygia, and spondylocarpotarsal fusion syndrome 1a and autosomal dominant intellectual developmental disorder. An important gene associated with Intellectual Developmental Disorder, Autosomal Dominant 42 is GNB1 (G Protein Subunit Beta 1). Affiliated tissues include eye and brain, and related phenotypes are global developmental delay and generalized hypotonia