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Antenatal and postnatal screeningPatterns of inheritance: family trees

Antenatal and postnatal screening are used to protect the health of mothers and babies. Antenatal techniques include ultrasound imaging, dating scans, blood and urine tests and diagnostic testing, such as amniocentesis, CVS and genetic screening. Postnatal screening can involve diagnostic testing such as PKU.

Part of Human BiologyPhysiology and Health

Patterns of inheritance: family trees

Pedigree analysis

Doctors can use a pedigree analysis chart to show how genetic disorders are inherited in a family.

They can use this to work out the probability (chance) that someone in a family will inherit a condition.

A pedigree analysis is usually undertaken if families are referred to a genetic counsellor following the birth of an affected child.

A visual to show a pedigree analysis chart that can help people find out about inherited disorders and diseases.

The pedigree analysis diagram is used to show the relationship within an extended family;

  • males are indicated by squares
  • females are represented by circles
  • affected individuals are red
  • unaffected individuals are blue
  • horizontal lines between males and females show that they have produced children

This analysis shows both male and female are affected, and every generation has affected individuals. There is one family group that has no affected parents or children, but the remaining two families have one affected parent and affected children too.