Pigmented hypertrichosis with insulin-dependent diabetes mellitus syndrome: A case series

Pigmented hypertrichosis with insulin-dependent diabetes mellitus (PHID) syndrome is a rare disease, and part of the cluster Histiocytosis-lymphadenopathy plus syndrome (H syndrome), which is associated with mutations in the SLC29A3 gene. Patients with PHID show clinical features of H syndrome, but also have insulin-dependent diabetes mellitus. The PHID associated diabetes has previously been described as predominantly in absence of pancreatic autoantibodies. Case Series Presentation: Through an open call in two international diabetes registers, clinical and genetic characteristics of 7 PHID patients in 6 treatment centres were collected after informed consent. All of them had consanguinity in their families, and their origins were located in North-African and Middle Eastern regions. 4 out of 7 patients had at least one positive pancreatic autoantibody. Our case series reveals that PHID exhibits a wide range of clinical symptoms and signs. When consanguinity is present in a patient with newly diagnosed diabetes, and/or if other atypical symptoms such as dysmorphic features, skin lesions, haematological abnormalities and developmental delay are present; threshold for genetic analysis should be low. Moreover, the presence of autoantibodies should not withhold genetic testing, as our case series contradicts the previous observation of predominant auto-antibody absence in PHID.