Genetic disorder

A genetic disorder, or genetic disease isdisease caused, at leastpart, bygenes ofperson withdisease. There arenumberpossible causesgenetic defects:

• They may be caused by an unwelcome mutation, asmost cancers.
• Theregenetic disorders caused byaccidental duplication ofchromosome, asDown syndrome, or repeated duplicationpart ofchromosome asFragile X syndrome.
• The defective genesoften inherited fromperson's parents. In this case,genetic disorderknown ashereditary disease. This can often happen unxpectedly when two healthy carriers ofdefective recessive gene reproduce, but can also happen whendefective genedominant.

Genetic disorders can frequently be explained as due tochange ofsingle DNA base ingene, resultingan enzyme or other protein either not being produced, or having altered functionality. This can be trivialrelatively harmlessits effects, such as color blindness, or lethal such as Tay-Sachs. Other disorders, though harmfulthose afflictedthem, appearoffer some advantagecarriers; ascarrierssickle cell anemiathalassaemia appearinghave enhanced resistancemalaria.

Several hereditary diseasessex-linked, meaning thatafflict one sex much more common thanother becausemutationlocated onX (or, rarely, onY) chromosome.

External links

• Genetic Disease Information fromHuman Genome Project