histiocytosis-lymphadenopathy plus syndrome
Definition A syndrome (OMIM:602782) characterised by a combination of features from 2 or more (of 4) histiocytic disorders, once thought regarded as distinct entities:
• Faisalabad histiocytosis Characterised by joint deformities, sensorineural hearing loss, and subsequent development of generalised lymphadenopathy and swellings in the eyelids that contain histiocytes
• H syndrome Characterised by cutaneous hyperpigmentation and hypertrichosis, hepatosplenomegaly, heart anomalies, and hypogonadism; hearing loss occurs in about half of patients.
• Pigmented hypertrichosis with insulin-dependent diabetes mellitus syndrome Characterised by predominantly antibody-negative insulin-dependent diabetes mellitus associated with pigmented hypertrichosis and variable occurrence of other features of H syndrome.
• Sinus histiocytosis with massive lymphadenopathy Characterised by lymph node enlargement in children often accompanied by fever, leukocytosis, elevated erythrocyte sedimentation rate, and polyclonal hypergammaglobulinaemia.
Molecular pathology Defects of SLC29A3, which encodes a glycosylated protein that plays a role in cellular uptake of nucleosides, nucleobases, and their therapeutic analogues, cause histiocytosis-lymphadenopathy plus syndrome.
Synonyms Faisalabad histiocytosis, H syndrome, histiocytosis and lymphadenopathy with or without cutaneous—cardiac—and/or endocrine features—joint contractures—and/or deafness, histiocytosis with joint contractures and sensorineural deafness, hyperpigmentation—cutaneous—with hypertrichosis—hepatosplenomegaly—heart anomalies—and hypogonadism with or without hearing loss, pigmented hypertrichosis with insulin-dependent diabetes mellitus, Rosai-Dorfman disease—familial, sinus histiocytosis and massive lymphadenopathy