PHID [pigmented hypertrichotic dermatosis with insulin-dependent diabetes mellitus, OMIM#602782] is a rare disorder characterized by childhood onset of pigmented hypertrichotic skin lesions and insulin-dependent diabetes mellitus, which is typically autoantibody negative. Circulating insulin is typically not detectable and cannot be induced in response to glucose administration, consistent with a defect of insulin production or secretion, rather than insulin resistance. PHID is allelic with H syndrome, which is associated with hyperpigmentation, hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, low height and hyperglycemia.
Cliffe et al (2009) identified homozygous mutations in the SLC29A3 gene [OMIM#602782] in five families affected by PHID. SLC29A3 encodes an equilibrative nucleoside transporter 3 protein, and studies of the Drosophilia ortholog of this protein have provided evidence that it interacts with the insulin signaling pathway. To date, missense, nonsense, splice site and frameshift mutations have been described in the SLC29A3 gene.