Postnatal Screening

• Postnatal Screening

  • Postnatal screening takes place after birth

  • It is used to detect metabolic disorders e.g. PKU.

  • Phenylketonuria (PKU) is an inborn error of metabolism

  • In PKU, a substitution mutation means that the enzyme which converts phenylalanine to tyrosineis non-functional.

  • If PKU is not detected and treated soon after birth the child's mental development is affected.

  • Individuals with high levels of phenylalanine are placed on a restricted diet.
• Genetic Screening and Counselling

  • Pedigree charts (family trees) are used to analyse patterns of inheritance in genetic screening.

  • Once the phenotype for a characteristic is known and a family tree is constructed most of the genotypes can be determined.

  • This information is used by genetic counsellors to advise parents of the possibility of passing on a genetic condition to their child.