Cockayne syndrome. Background:. Cockayne syndrome:
is a rare and devastating genetic disease. It is present in about 1/100,000 live births. Its inheritance is autosomal recessive. In other words, it occurs if both the father and the mother pass on a damaged gene to the affected child, with the parents themselves having no health problems related to CS, and with 1/4 of the siblings expected to also have CS.
the classic form
a more severe form with symptoms present at birth
a milder form
By the time the disease has fully manifested, height, weight, and head circumference are far below the fifth percentile.
dwarfism(侏儒) with thinning of the skin and hair, sunken eyes, and a stooped standing posture
Patients are at risk for postnatal growth failure, pigmentary retinal degeneration, and premature death before adulthood.
The oldest CS patient known to Share and Care Cockayne Syndrome Network is in the late 30s. For children born with cataracts, the life expectancy is 12 years, and many CS patients die in infancy. Both the severity of the genetic damage in the individual patient, and the quality of care including ensuring adequate food intake, are important determinants of the lifespan.
Pathologic studies reveal diffuse and extensive demyelination(脱髓鞘) in the central and peripheral nervous systems.
This includes the CS-A gene, ERCC8 , in about 25% of cases; and the CS-B gene, ERCC6, in about 75% of cases.
CKN1 is caused by a defect in the CS type A gene (CSA or ERCC8) located on chromosome 5.
Affected persons inherit 2 mutant genes, one from each parent. Cells carrying ERCC8 mutations are hypersensitive to UV light. They do not recover the ability to synthesize RNA after exposure to UV light.
In addition, the cells cannot remove and degrade DNA lesions from strands that have active transcription.
There is no cure for Cockayne syndrome, so threatmentfocuses on relieving symptoms and improving the person’s quality of life. Physical and occupation therapy can help maintain joint function and reduce muscle contractures.
Treatment of patients with CKN1 depends solely on the presenting symptoms. Physical therapy helps prevent contractures and helps maintain ambulation
Physical therapy is essential to enable patients to avoid joint contractures and to prolong ambulation .
protect himself from sunlight with clothing and sunscreen, to reduce cell damage.