620- intro to pedigrees

pedigree

french "pie de grue" the cranes foot
first used in the 15th century

Historical symbols

Pliny Earle (1845) used circles and squares to illustrate affected vs unaffected
Francis Galton (1869) used venus and mars to indicate gender

Eugenics and Pedigrees

1907- eugenics education society established
collected pedigrees to show these traits have significant genetic components as proof of need for eugenics (criminality, pauperism, Feeble-mindedness)

Early Validation for Pedigrees (Davenport 1915)

-pure love of knowledge as well as to stimulate interest in the origin of an individuals taste, capacities and limitations
-to allow society to implement effective and humane treatment of delinquent individuals
- to permit vocational selection based on special capacities
- to help individuals achieve their educational potential
- to select proper "marriage mates"

Why do we take a family history?

- Gather information critical to proper risk assessment and diagnosis
- identify individuals from at risk populations
- identify other possible risks, other family members, other disorders
- build rapport with couple by showing interest in them and their family, listening to their stories, chatting appropriately
- give information on social realtionships

Why document as a pedigree?

- quick standardized way for healthcare professionals to visualize and communicate family history
- uniform nomenclature enables consistant documentation across providers and healthcare settings
- can be updated at subsequent appointments or shared across health systems

Gender symbols

Male: Square
Female: Circle
Gender unknown: Diamond

Proband

first person in the family to bring a genetic condition to a healthcare appointment.
indicated by an arrow with a P

Consultant

person who comes in for testing, can also be the proband

AFAB

assigned female at birth - indicated by square with AFAB written beneath

AMAB

assigned male at birth - indicated by circle with AMAB written beneath

UAAB

unassigned at birth

affected individual

Fully shaded within a pedigree

historian

person relaying family history information

clinical pedigrees should include

- name of proband/consultant
-family names/initials of relatives for identification as appropriate
-name and title of person recording pedigree (GC)
-historian
-date of intake
-indication for taking pedigree
-ancestry of both sets of grandparents when clinically relevant

why equity matters in pedigree collection

low income, racial/ethnic minority and poorly educated individuals are less likely to collect or share family health history with a provider

practical considerations for inclusive pedigree taking

acknowledge that family structures vary widely
consider patients that may lack knowledge of biological relatives

summary questions to ask

multiple SABs or still birth?
any early death?
anyone with surgery as a child?
any birth anomalies?
any intellectual or physical disabilities?
any cancer?
any chronic conditions run in the family?
what else have I not asked that you think is important to know?