The H syndrome is caused by mutations in the nucleoside transporter hENT3.

The H syndrome is a recently reported autosomal-recessive disorder characterized by cutaneous hyperpigmentation, hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, short stature, hallux valgus, and fixed flexion contractures of the toe joints and the proximal interphalangeal joints. Homozygosity mapping in five consanguineous families resulted in the identification of mutations in the SLC29A3 gene, which encodes the equilibrative nucleoside transporter hENT3. Three mutations were found in 11 families of Arab and Bulgarian origin. The finding of several different mutations in a small geographic region implies that the H syndrome might be rather common. The identification of mutations in the SLC29A3 gene in patients with a mild clinical phenotype suggests that this is a largely underdiagnosed condition and strongly suggests that even oligosymptomatic individuals might have the disorder.

The H syndrome: a genodermatosis characterized by indurated, hyperpigmented, and hypertrichotic skin with systemic manifestations.

BACKGROUND: The association of cutaneous hyperpigmented, hypertrichotic, and indurated patches associated with hearing loss, short stature, cardiac anomalies, hepatosplenomegaly, scrotal masses, and hypogonadism has not, to our knowledge, been previously recognized as a disease entity. OBJECTIVE: We describe 10 patients with the above-mentioned findings. METHODS: Patients were clinically examined and extensive laboratory evaluation was performed. RESULTS: We describe 10 patients from 6 Arab consanguineous families with hyperpigmented, hypertrichotic, and indurated cutaneous patches involving the middle and lower parts of their bodies. In addition, patients displayed short stature, sensorineural hearing loss, cardiac anomalies, hepatosplenomegaly, and scrotal masses. Laboratory evaluation revealed growth hormone deficiency and hypergonadotropic hypogonadism with azoospermia. Cutaneous histopathologic examination showed hyperpigmentation of the basal layer with seborrheic-keratosis-like acanthosis, histiocytic infiltration, and a perivascular mononuclear infiltrate with plasma cells and mast cells throughout the dermis and subcutaneous fat. Comparison with several patients, recently reported in the medical literature, with similar cutaneous findings is made. LIMITATIONS: Laboratory evaluation in some patients was incomplete because of lack of cooperation. CONCLUSIONS: We suggest that our patients represent a novel multisystemic autosomal recessive inherited disorder. We call this constellation of symptoms the "H syndrome."

Evidence for clinical and genetic heterogeneity in hereditary benign telangiectasia.

BACKGROUND: Telangiectases are abnormal dilatations of end vessels in the subpapillary plexus of the papillary dermis. Hereditary benign telangiectasia (HBT) (OMIM 187260) is a genetic skin disorder, characterized by multiple cutaneous telangiectases appearing in the first years of life in various locations. Several familial cases of HBT have been described displaying autosomal dominant inheritance. In some of the described pedigrees, telangiectases are limited to sun-exposed areas, whereas in others lesions are randomly distributed over the body. The disorder has been previously mapped to a 7Mb interval on chromosome 5q14 (CMC1 locus) in an Italian pedigree with randomly distributed telangiectases. OBJECTIVES: A large pedigree of HBT with photodistributed lesions is described. We sought to determine whether photodistributed HBT is linked to the CMC1 locus. METHODS: In all, 35 family members were examined. DNA was extracted from blood and saliva samples. Linkage analysis to CMC1 locus on chromosome 5q14 was screened by using 3 polymorphic markers. RESULTS: In all, 23 family members were found to have variable numbers of cutaneous radiating macular telangiectases, measuring 1 to 3 cm and distributed over the face, back of the hands, and forearms. HBT in this family is inherited in an autosomal dominant pattern with incomplete penetrance. Linkage to the CMC1 locus was excluded. LIMITATION: Only one family, although very large, was studied in this project. CONCLUSIONS: Clinical and genetic heterogeneity is evident in HBT. Photodistributed HBT is not related pathogenically to capillary malformations or to randomly distributed hereditary telangiectases and should be recognized as a separate entity.