H syndrome: novel and recurrent mutations in SLC29A3

The H syndrome (OMIM 612391) is a recently described autosomal recessive disorder characterized by cutaneous hyperpigmentation, hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, short stature (low height), hyperglycaemia/diabetes mellitus, hallux valgus, and fixed flexion contractures of the toe and finger joints.(1,2) Histologically, there is an inflammatory infiltrate consisting mainly of histiocytes, later replaced by fibrosis of the deep dermis and subcutis.(3) In total, 31 patients have been reported in the literature with the clinical phenotype characteristic of this syndrome.(1-7)