H syndrome, also known as Histiocytosis-lymphadenopathy plus syndrome or PHID, is a rare genetic condition caused by mutations in the SLC29A3 gene which encode the human equilibrative nucleoside transporter (hENT3) protein.Moynihan L M, Bundey SE, Heath D, Jones EL, McHale DP, Mueller RF, Markham, AF, Lench NJ (1998) Autozygosity mapping, to chromosome 11q25, of a rare autosomal recessive syndrome causing histiocytosis, joint contractures, and sensorineural deafness. Am J Hum Genet 62: 1123-1128 It is also known as Faisalabad histiocytosis, familial Rosai-Dorfman disease, sinus histiocytosis with massive lymphadenopathy and pigmented hypertrichosis with insulin-dependent diabetes mellitus syndrome.

Presentation

This syndrome has a number of different clinical features many of which start with the letter 'H' giving rise to the name of the syndrome. These features include * Hyperpigmentation * Hypertrichosis * Hepatosplenomegaly * Hearing loss * Heart anomalies * Hypogonadism * Low height (short stature) *

Hyperglycemia Hyperglycemia is a condition in which an excessive amount of glucose circulates in the blood plasma. This is generally a blood sugar level higher than 11.1 mmol/L (200 mg/dL), but symptoms may not start to become noticeable until even ...

/ diabetes mellitus * Hallux valgus/flexion contractures Exophthalmos, malabsorption and renal anomalies have also been reported.

Genetics

The SLC29A3 gene is located on the long arm of chromosome 10 (10q22).The causative gene was identified in 2010.Morgan NV, Morris MR, Cangul H, Gleeson D, Straatman-Iwanowska A, Davies N, Keenan S, Pasha S, Rahman F, Gentle D, Vreeswijk MPG, Devilee P, and 10 others. Mutations in SLC29A3, encoding an equilibrative nucleoside transporter ENT3, cause a familial histiocytosis syndrome (Faisalabad histiocytosis) and familial Rosai-Dorfman disease. PLoS Genet. 6: e1000833

Pathogenesis

This is not understood at present.

Management

There is no curative treatment for this condition at present. Management is directed to the clinical features.

History

This condition was first described in 1998.Moynihan L M, Bundey SE, Heath D, Jones EL, McHale DP, Mueller RF, Markham, AF, Lench NJ (1998) Autozygosity mapping, to chromosome 11q25, of a rare autosomal recessive syndrome causing histiocytosis, joint contractures, and sensorineural deafness. Am J Hum Genet 62: 1123-1128

References

External links

{{DEFAULTSORT:H syndrome Autosomal recessive disorders Genetic syndromes Rare syndromes