MedGen

Cataracts, hearing impairment, nephrotic syndrome, and enterocolitis-1 (CHINE1) is an X-linked syndromic disorder that is phenotypically more severe in males than females. Affected males present with the full constellation of symptoms in early infancy, resulting in death in early childhood. Affected females develop early-onset hearing impairment, often with early-onset cataracts, but only rarely have nephrotic syndrome or proteinuria; they do not have enterocolitis. The variable manifestations in females may be influenced by skewed X-inactivation. Telomeres are shortened, but classic mucocutaneous features of DKCX are not typically observed. CHINE1 is due to a ribosomal pseudouridylation defect (Balogh et al., 2020). See also CHINE2 (620425), caused by mutation in the NOP10 gene (606471). [from OMIM]

Hoyeraal-Hreidarsson syndrome is a multisystem disorder affecting males and is characterized by aplastic anemia, immunodeficiency, microcephaly, cerebellar hypoplasia, and growth retardation. [from OMIM]

Dyskeratosis congenita and related telomere biology disorders (DC/TBD) are caused by impaired telomere maintenance resulting in short or very short telomeres. The phenotypic spectrum of telomere biology disorders is broad and includes individuals with classic dyskeratosis congenita (DC) as well as those with very short telomeres and an isolated physical finding. Classic DC is characterized by a triad of dysplastic nails, lacy reticular pigmentation of the upper chest and/or neck, and oral leukoplakia, although this may not be present in all individuals. People with DC/TBD are at increased risk for progressive bone marrow failure (BMF), myelodysplastic syndrome or acute myelogenous leukemia, solid tumors (usually squamous cell carcinoma of the head/neck or anogenital cancer), and pulmonary fibrosis. Other findings can include eye abnormalities (epiphora, blepharitis, sparse eyelashes, ectropion, entropion, trichiasis), taurodontism, liver disease, gastrointestinal telangiectasias, and avascular necrosis of the hips or shoulders. Although most persons with DC/TBD have normal psychomotor development and normal neurologic function, significant developmental delay is present in both forms; additional findings include cerebellar hypoplasia (Hoyeraal Hreidarsson syndrome) and bilateral exudative retinopathy and intracranial calcifications (Revesz syndrome and Coats plus syndrome). Onset and progression of manifestations of DC/TBD vary: at the mild end of the spectrum are those who have only minimal physical findings with normal bone marrow function, and at the severe end are those who have the diagnostic triad and early-onset BMF. [from GeneReviews]