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Cockayne syndrome, TYPE B (CSB)

CSB is caused by mutation in the gene encoding the group 6 excision-repair cross-complementing protein (CSB/ERCC6).

Cockayne syndrome is a rare disorder characterized by cutaneous sensitivity to sunlight, abnormal and slow growth, cachectic dwarfism, progeroid appearance, progressive pigmentary retinopathy and sensorineural deafness. There is delayed neural development and severe progressive neurologic degeneration resulting in mental retardation. Two clinical forms are recognized: in the classical form or Cockayne syndrome type 1, the symptoms are progressive and typically become apparent within the first few years or life; the less common Cockayne syndrome type 2 is characterized by more severe symptoms that manifest prenatally. Cockayne syndrome shows some overlap with certain forms of xeroderma pigmentosum. Unlike xeroderma pigmentosum, patients with Cockayne syndrome do not manifest increased freckling and other pigmentation abnormalities in the skin and have no significant increase in skin cancer.

Ocular Features: The eyes are deep-set.  Congenital cataracts are present in 30% of infants. The aggressive course of this form of CS has precluded full delineation of the ocular features but infants have been described with microphthalmos, microcornea and iris hypoplasia. 
Systemic Features: Evidence of somatic and neurologic delays is present at birth or shortly thereafter with microcephaly and short stature.  Infants never develop normal milestones and may not grow in size beyond that of a 6 month-old child.  Communication skills are minimal.  They have a progeroid appearance, age rapidly, and most do not live beyond 5 years of age. Feeding problems are common with considerable risk of aspiration, a common cause of respiratory infections and early death.  Severe flexion contractures develop early and may interfere with motor function.  Tremors and weakness contribute as well.  The skin is sensitive to UV radiation in some but not all patients.  However, the frequency of skin cancer is not increased.  Endogenous temperature regulation may be a problem.

OTHER NAME(S): CSB syndrome

ABREVIATION(S):
CSB

TYPE: microcephaly, mental retardation (MR), psychomotor impairment, sensitivity to radiation, NO CANCER development, eye or vision problem, cerebro-oculo-facio-skeletal-syndrome (COFS)

Related patway(s): nucleotide excision repair (NER)

DNAtraffic protein(s) related to disease: ERCC6 (CSB)

OMIM: 133540

Last modification date: Aug. 17, 2011