SNP Shot: Genomic Insights

Cockayne syndrome is an uncommon genetic condition marked by several key features. These include an unusually small head (microcephaly), difficulty gaining weight and growing at the expected pace (failure to thrive) resulting in significantly reduced height, and delayed developmental milestones. These symptoms typically become noticeable in infancy and tend to worsen as the individual ages. A common characteristic is heightened sensitivity to sunlight (photosensitivity), where even minimal sun exposure can lead to sunburn or skin blistering in many cases. Additional symptoms often encompass hearing impairment, vision impairment, significant dental cavities, skeletal abnormalities, chronically cold hands and feet, and structural changes in the brain detectable through imaging scans.

Individuals with Cockayne syndrome exhibit a severe adverse reaction to the antibiotic metronidazole. Ingesting this medication can lead to life-threatening liver failure in affected individuals.

Cockayne syndrome is sometimes classified into types I, II, and III based on the severity of symptoms and the age at which they appear. However, the distinctions between these types are not always well-defined, and some experts believe the symptoms represent a continuous spectrum rather than distinct categories. Cockayne syndrome type II is also referred to as cerebro-oculo-facio-skeletal (COFS) syndrome. While some consider COFS syndrome a separate, though similar, condition, others classify it as a part of the broader Cockayne syndrome disease spectrum.

Inheritance:

The inheritance pattern for this condition is autosomal recessive. This means that both copies of the relevant gene in each cell must carry a mutation for the condition to manifest. Individuals with autosomal recessive conditions inherit one mutated copy of the gene from each parent. The parents themselves typically do not exhibit any signs or symptoms of the condition, as they each possess only one copy of the mutated gene.