H syndrome

H syndrome (MIM.612391) is a recently described autosomal recessive genodermatosis characterized by indurated, hyperpigmented, and hypertrichotic skin and systemic manifestations including hepatosplenomegaly, cardiac anomalies, hearing loss, hypogonadism, low height, hypertriglyceridemia, hallux valgus, and flexion contractures.

H syndrome results from mutations in the SLC29A3 gene, which encodes the human equilibrative nucleoside transporter hENT3.

The cutaneous histopathology is characterized by a striking mononuclear cell infiltrate in the dermis consisting of CD68+ monocyte-derived cells and CD34+ and factor XIIIa+ dendrocytes.