hemoglobin H disease

An alpha thalassemia that has_material_basis_in contiguous gene deletion of the hemoglobin alpha-1 (HBA1) and alpha-2 (HBA2) genes on one chromosome 16, and a defect, deletional or nondeletional, in either HBA1 or HBA2 on the other.

alpha-thalassemia myelodysplasia syndrome

A syndrome characterized by acquired alpha-thalassemia in association with a multilineage myelodysplasia that has_material_basis_in somatic mutation in the ATRX gene on chromosome Xq21.1.

hypomyelinating leukodystrophy 6

A hypomyelinating leukodystrophy characterized by infant or early childhood onset of delayed motor development and gait instability, followed by extrapyramidal movement disorders, progressive spastic tetraplegia, ataxia, hypomyelination, cerebellar atrophy, and atrophy or disappearance of the putamen that has_material_basis_in heterozygous mutation in the TUBB4A gene on chromosome 19p13.

xeroderma pigmentosum group D

A xeroderma pigmentosum that has_material_basis_in homozygous or compound heterozygous mutation in the excision repair gene ERCC2 on chromosome 19q13.

COACH syndrome

A syndrome characterized by autosomal recessive inheritance of cerebellar vermis hypo/aplasia, oligophrenia, ataxia, ocular coloboma, and hepatic fibrosis that has_material_basis_in homozygous or compound heterozygous mutation in one of 3 genes (TMEM67, CC2D2A, RPGRIP1L).

junctional epidermolysis bullosa Herlitz type

A junctional epidermolysis bullosa characterized by autosomal recessive inheritance of severe blisters and extensive erosions, localized to the skin and mucous membranes, resulting in a failure to thrive and that has_material_basis_in mutations in any 1 of the 3 genes encoding the subunits of laminin-5: LAMA3, LAMB3, and LAMC2. The Herlitz type is more severe than the related non-Herlitz type of junctional epidermolysis bullosa.

histiocytosis-lymphadenopathy plus syndrome

A syndrome characterized by histiocytosis, hyperpigmentation, hypertrichosis, hepatosplenomegaly, heart anomalies, hearing loss, hypogonadism, and reduced height that has_material_basis_in homozygous or compound heterozygous mutation in SLC29A3 on 10q22.1. This syndrome comprises features from 4 histiocytic disorders that were previously considered distinct: Faisalabad histiocytosis, sinus histiocytosis with massive lymphadenopathy, H syndrome, and pigmented hypertrichosis with insulin-dependent diabetes mellitus syndrome.

immunodeficiency 23

A combined T cell and B cells immunodeficiency characterized by marked atopy and autoimmunity caused by increased T(H)2 and T(H)17 cytokine production by CD4(+) T cells, T-cell lymphopenia, reduced memory B-cell numbers, recurrent respiratory and skin infections beginning in early childhood, increased serum IgE, and variable developmental delay or intellectual impairment that has_material_basis_in homozygous or compound heterozygous mutation in the PGM3 gene on chromosome 6q14.1.

X-linked mental retardation-hypotonic facies syndrome-1

A syndromic X-linked intellectual disability that is characterized primarily by severe mental retardation, dysmorphic facies, and a highly skewed X-inactivation pattern in carrier women and that has_material_basis_in mutation in the ATRX gene. X-linked mental retardation-hypotonic facies syndrome comprises several syndromes previously reported separately. These include Carpenter-Waziri, Holmes-Gang, and Smith-Fineman-Myers syndromes. X-linked alpha-thalassemia/mental retardation syndrome is an allelic disorder with a similar phenotype with the addition of alpha-thalassemia and Hb H inclusion bodies in erythrocytes.

reactive arthritis

An arthritis that is an autoimmune disease which develops due to an infection located elsewhere in the body.