ABSTRACT
The genetic defect can be detected using Polymerase chain reaction and this can be used to screen for carriers or affected pregnancies using chorionic villous sampling. Deoxyribonucleic acid technology is used to determine the genetic father in paternity disputes and also in forensic science to identify body tissues and fluids. Genes, located on chromosomes, comprise a sequence of bases on deoxyribonucleic acid and code for the synthesis of proteins by ribonucleic acid (RNA) in its ‘messenger’ form (mRNA). The mRNA from a particular gene can be identified and characterized. Deoxyribonucleic acid can easily be prepared from very small amounts of biological samples, often blood. This essentially involves three steps: leucocyte lysis, chloroform/phenol extraction to remove contamination by proteins, followed by proteinase and RNAase treatment to remove remaining protein and RNA contamination. Females are only clinically affected in the extremely rare circumstance when they are homozygous for the abnormal gene.
