 It can also be associated with mutations in the histone methyltransferase "NSD1" gene on chromosome 5q35.The functions of NSD1 are not clearly known, but it is thought to act as a factor in influencing transcription, which contains domains involved in chromatin-mediated regulation during development.Most cases are found to be sporadic, with no family history of the syndrome, although there have been a few cases in families where autosomal dominant inheritance has been reported.