The best and easiest way to record genetic information is to draw a pedigree.  The agreed notation is shown in the figure. 

You may be asked to draw a pedigree in the end of module examination

Guidelines include:

• Build up the tree from the “bottom” starting with the affected child and siblings. “Please give me the names of your children, and their dates of birth in order of their ages, starting with the eldest first.” (The usual convention is to place siblings in birth order with the firstborn on the left.)

• Choose one of the parents (usually the mother) and ask about her siblings and their chldren, and then her parents, moving from generation to generation.

• Add information on the paternal side of the family

• Use clear symbols eg circles for females, squares for males. Fill in the symbol if the person is affected. For a partnership, the usual convention is to place the male partner on the left.

• Put a sloping line through the symbol (from the bottom left hand to the top right hand corners) if the person has died. If appropriate, record the cause of death and age at death.

• Record names (check spelling!), maiden names and dates of birth (rather than ages whenever possible)

• Ask for miscarriages, stillbirths or deaths in each partnership: “How many children have you had?  Have you lost any children? Have you had any previous partners?”

• Information on parent occupations, past medical and drug history, pregnancy and birth history should be noted, especially where a child has a dysmorphic syndrome.

• Ask about consanguinity: “Are you and your partner related? Are there any surnames in common in the family?”Sometimes it is helpful to indicate the person seeking advice with an unlabelled arrow. This person is called the consultand, who may not be affected.

• Record at least basic details on both sides of the family, even if it appears that a disorder is segregating on one side.

• Date and sign the pedigree.

Typical pedigrees will cover three generations. However, when the mode of inheritance is certain from the diagnosis (for example, a known  autosomal recessive condition or a pregnancy with trisomy 21) it may not be necessary to record personal details on all family members in as much detail as would be required for an unknown disease. 

It is recommended that consent is sought from the couple to share their medical information and the results of tests with other members of their families.