Skip to Content
Printer friendly PDF
Please follow the instructions below when creating a pedigree. Additional resources can be found here: http://www.nsgc.org/About/FamilyHistoryTool/tabid/226/Default.aspx
Bennett, R.L., French, K.S., Resta, R.G. & Doyle, D.L. Standardized human pedigree nomenclature: update and assessment of the recommendations of the National Society of Genetic Counselors. J Genet Couns 17, 424-33 (2008).
The following information must be included on the pedigree:
Begin by drawing a solid square (male) or circle (female) for the first person with disease who presented to medical attention. This individual is called the proband. Place an arrow on the lower left corner of this individual to indicate he/she is the proband.
Write the person's first name, or initials below the symbol.
Write the person's current age below the symbol.
Indicate the disease or disorder the individual has along with the age of onset below the symbol.
Next, draw the person’s parents. To indicate partners/marriage draw a horizontal line connecting the two symbols (see below). If the individuals are consanguineous (i.e. related) indicate consanguinity with a double horizontal line. If the degree of consanguinity is not clear on the pedigree, please write above the relationship line, i.e. “2nd cousins.”
Add the parents current age, or age at death (d. age or year) with cause of death. Also, indicate any diagnoses (dx. Disease X) the individuals may have along with the age at diagnosis (dx. Disease X 50y.o.).
Draw any siblings in birth order from left (oldest) to right (youngest). Siblings are connected by a horizontal line above the symbols, with vertical lines connecting the symbols to the horizontal line. Leave space to add any partners and children.
Add aunts, uncles, grandparents in the same manner. All affected individuals should be included in the pedigree and as many unaffected individuals as possible (parents, grandparents, and siblings of any affected individual).
For each individual add the following below their symbol
** The current place of residence (City, State) for each individual willing to participate in the study can be recorded on the pedigree, or must be provided to the IIHG as a separate list.
At the top of the pedigree write the ethnicity of each grandparent. Record the date the pedigree was obtained.
Finally, draw a key in the lower left corner indicating what the shading represents.
Autosomal Dominant Example: Marfan Syndrome
Autosomal Recessive Example: Cystic Fibrosis
Living Unaffected female: Clear circleLiving Unaffected male: Clear squareUnknown gender: Clear diamondPregnancy symbols:
Gender unknown Female fetus Male fetus
Living Affected female: Black circle
Living Affected male: Black square
Adoption, place brackets around the adopted individual. A dashed offspring line indicates the individual was adopted into the family, and a solid line indicates the individual was adopted out of the family.
Adopted into family male Adopted out of family male
Deceased: symbol with a diagonal line
Deceased male Deceased female Individual with multiple diagnoses
Marriage/Mating Line: horizontal line connecting 2 symbols at the center of each symbol
Separated, Divorce, Relationship no longer exists Line: horizontal line connecting 2 symbols with 2 diagonal hash marks.
Offspring Line: Vertical line from the center of the mating line to the center of the offspring symbol or to the sibling line.
1 male child
Children from a previous partner (stepchildren).
Mike and Jane have one son, and Jane has a daughter from a previous marriage.
Sibling Line: Horizontal line above the offspring and connected by vertical lines. Example: brother and sister siblings.
Brother and sister siblings with two parents
Twins: Indicated by two diagonal vertical lines originating from the same point.
No children: A vertical line with 2 hash marks at the end. Indicate if an adult does not have children by choice (c), infertility (i).