Neil V. Morgan 1 , Mark R. Morris 1 , 2 , Hakan Cangul 1 , 3 , Diane Gleeson 4 , Anna Straatman-Iwanowska 1 , Nicholas Davies 5 , Stephen Keenan 4 , 6 , Shanaz Pasha 1 , Fatimah Rahman 1 , Dean Gentle 1 , 2 , Maaike P. G. Vreeswijk 7 , Peter Devilee 7 , 8 , Margaret A. Knowles 9 , Serdar Ceylaner 10 , Richard C. Trembath 11 , Carlos Dalence 12 , Erol Kismet 13 , Vedat Köseoğlu 13 , Hans-Christoph Rossbach 12 , Paul Gissen 1 , David Tannahill 4 , 14 , Eamonn R. Maher 1 , 2 , 15 , *
5 February 2010
The histiocytoses are a heterogeneous group of disorders characterised by an excessive number of histiocytes. In most cases the pathophysiology is unclear and treatment is nonspecific. Faisalabad histiocytosis (FHC) (MIM 602782) has been classed as an autosomal recessively inherited form of histiocytosis with similarities to Rosai-Dorfman disease (RDD) (also known as sinus histiocytosis with massive lymphadenopathy (SHML)). To elucidate the molecular basis of FHC, we performed autozygosity mapping studies in a large consanguineous family and identified a novel locus at chromosome 10q22.1. Mutation analysis of candidate genes within the target interval identified biallelic germline mutations in SLC29A3 in the FHC kindred and in two families reported to have familial RDD. Analysis of SLC29A3 expression during mouse embryogenesis revealed widespread expression by e14.5 with prominent expression in the central nervous system, eye, inner ear, and epithelial tissues including the gastrointestinal tract. SLC29A3 encodes an intracellular equilibrative nucleoside transporter (hENT3) with affinity for adenosine. Recently germline mutations in SLC29A3 were also described in two rare autosomal recessive disorders with overlapping phenotypes: (a) H syndrome (MIM 612391) that is characterised by cutaneous hyperpigmentation and hypertrichosis, hepatomegaly, heart anomalies, hearing loss, and hypogonadism; and (b) PHID (pigmented hypertrichosis with insulin-dependent diabetes mellitus) syndrome. Our findings suggest that a variety of clinical diagnoses (H and PHID syndromes, FHC, and familial RDD) can be included in a new diagnostic category of SLC29A3 spectrum disorder.
The histiocytoses are a group of systemic disorders usually confined to childhood and are caused by an excessive number of histiocytes which phagocytose other cells and process antigens. Although nearly a century has passed since histiocytic disorders were recognised, their pathophysiology remains largely unclear, and treatment is nonspecific. The identification of SLC29A3 mutations as the molecular basis for a familial form of syndromic histiocytosis (FHC/RDD) confirms a direct link between Faisalabad histiocytosis and Rosai-Dorfman disease and links these disorders to other SLC29A3-associated phenotypes.