PHF8

PHD finger protein 8 is a protein that in humans is encoded by the PHF8 gene.

Function

PHF8 belongs to the family of ferrous iron and 2-oxoglutarate dependent oxygenases, and is active as a histone lysine demethylase with selectivity for the di-and monomethyl states.

Clinical significance

Mutations in PHF8 cause Siderius type X-linked mental retardation (XLMR) (OMIM 300263). In addition to moderate intellectual disability, features of the Siderius-Hamel syndrome include facial dysmorphism, cleft lip and/or cleft palate, and in some cases microcephaly. A chromosomal microdeletion on Xp11.22 encompassing all of the PHF8 and FAM120C genes and a part of the WNK3 gene was reported in two brothers with autism spectrum disorder in addition to Siderius-type XLMR and cleft lip and palate.

This catalytic activity is disrupted by clinically known mutations to PHF8, which were found to cluster in its catalytic JmjC domain. The F279S mutation of PHF8, found in 2 Finnish brothers with mild intellectual disability, facial dysmorphism and cleft lip/palate, was found to additionally prevent nuclear localisation of PHF8 overexpressed in human cells.