Cockayne syndrome
Incidence
More than 150 cases reported. AR disorder due to defective repair of transcriptionally active DNA. No increase incidence of cancer.
Clinical Characteristics
At birth pts look normal but may have intrauterine growth retardation (IUGR). Severe FTT is noted on second to 3rd year with severe dwarfism, often with dysproportionate long limbs. Developmental delay. Normal or advanced bone age. Thick skull bones and kyphoscoliosis. Joint deformities. There is cutaneous photosensitivity since early infancy (usually first 6 months). There may be anhydrosis or poor lacrimation. Marked microcephaly (3-6 SD below nl), worse than delayed body growth. There is retinitis pigmentosa in 70% and early nerve deafness. There are special facial features such as sunken eyes, large ears, prominent beak-like nose, thin pigmented skin, mandible anomaly, frequent caries, resemblace with Progeria. Absent ERG. They develop cataract which lead to blindness and pendular nystagmus. Optic atrophy in 50%. May have corneal opacity. Severe global developmental delay, with IQ < 30. Progressive slow deterioration with eventual pyramidal symptoms, ataxia, tremor, sometimes athetosis, also seizures. Often peripheral neuropathy with absent DTRs and slow NCV and muscle atrophy. Death by 2nd to 3rd decade (mean age 12 yrs). No treatment available. CSF normal. EEG non-specific. May have hyperbetalipoproteinemia and hyperinsulinism. At times hyperglycemia. May develop high blood pressure and renal failure late in the course. Ct scan show basal ganglia and dentate nuclei calcification with leukodystrophy. MRI show white matter diffuse abnormality (high signal on T2 = leukodystrophy. Marked ventricular dilatation. Normal pressure hydrocephalus?. No sensitivity to X-irradiation. There is inhibition of RNA synthesis increased after UV irradiation.
Precipitants
no
Provocation Tests
no
Diagnostic Procedures
Clinical and radiological diagnosis. Inhibition of RNA synthesis increased after UV irradiation.