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6 Yours, Mine, and Ours—The Blended Family

6 Yours, Mine, and Ours—The Blended Family

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Figure 3.4



The most common pedigree symbols. Pregnancy-related symbols are shown in Figure 3.5.



YOURS, MINE, AND OURS—THE BLENDED FAMILY



Figure 3.5



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Pedigree symbols related to pregnancy.



sibling group on the pedigree, ask if they share the same mother and father. If the

answer is no, ask “Which of your brothers and sisters share the same mother and which

share the same father?” Not uncommonly patients confuse half-sibs from step-sibs.

If there is a big gap in age between siblings, this is a clue that they may be

half-siblings. The gap may also be an indication of a period of infertility.

It is not necessary to include each partner of an individual on a pedigree—doing so

can make a pedigree quite complicated as is illustrated in actress Elizabeth Taylor’s

marriage history shown in Figure 3.6.



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Figure 3.6 A pedigree of actress Elizabeth Taylor demonstrating how to illustrate multiple marriage partners, step-children, and half siblings. (Source:

www.celebsite.com.)



ADOPTION



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3.7 PEDIGREE SYMBOLS RELATED TO PREGNANCY

AND REPRODUCTION

The various pedigree symbols related to pregnancy, spontaneous abortion, termination

of pregnancy, stillbirth, and infertility are shown in Figure 3.5. If the gestational age is

known, place the gestational age in weeks (wk.) below the symbol. An approximation

of dates can be shown such as “∼12 wk.” Usually the gestational age is stated as the

date from the first date of the last menstrual period (LMP) or the estimated date of

delivery (EDD). The older terminology of estimated date of confinement (EDC) is

considered archaic. Pregnancy dating by ultrasound can be noted as “US 12 wk.”

A stillbirth (SB) is defined as “the birth of a dead child with gestational age noted”

(Bennett et al., 1995).

If the gender of the fetus is known then one can write “male” or “female” under the

symbol. This is preferable to making the symbol a square or a circle. If a chromosome

study has confirmed the sex of the fetus, this can be noted under the symbol as

“46,XX” or “46,XY.”

3.8 ASSISTED REPRODUCTIVE TECHNOLOGIES (ART) AND USE

OF DONOR GAMETES

The importance of recording family history for persons conceived through ART,

including information on the family history of egg or sperm donors is detailed in

Chapter 8. The symbols to use in recording this information are noted in the tables to

Chapter 8. Some birth defects may be related to assisted reproductive technologies

(e.g., in vitro fertilization, frozen embryos), and therefore the method of ART should

be recorded on the pedigree.

3.9 ADOPTION

It is important to distinguish a person who is adopted in to a family (a nonbiological

relative) from a person who is adopted out (a biological relative). To symbolize

adoption, brackets are placed around the symbol for male (square) or female (circle)

or unknown (diamond). If a person or couple adopts an individual, the individual’s

line is dotted (indicating a nonbiological relationship). A person who is placed for

adoption has a solid individual’s line to the birth parents.

It is not uncommon for a family member to adopt a relative—for example, a sibling

adopting a niece or nephew, or grandparents adopting a grandchild. The method of

recording this situation on a pedigree is shown in Figure 3.7.

When a person or couple adopts a child it is useful to inquire if there was a medical

reason; perhaps an adoptive parent had a genetic condition or the couple who adopted

the child experienced infertility. The reason can be noted below the line of descent.

When a child is placed for adoption, information about the child’s medical heritage

is usually given to the adoptive parents (see Chapter 7). A sample adoptive medicalfamily history form can be found in Appendix A.4.



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GETTING TO THE ROOTS: RECORDING THE FAMILY TREE



Figure 3.7



Pedigree symbolization of adoption.



3.10 INFERTILITY AND NO CHILDREN BY CHOICE

If a person or couple is of reproductive age and has no children, inquire if this is by

choice or for a biological reason. The cause of infertility should be noted below the

individual’s line (e.g., azoospermia, endometriosis, etc.).



3.11 AFFECTED STATUS: SHADING THE PEDIGREE SYMBOLS

Accurately documenting who is affected and unaffected on a pedigree is critical for

pedigree analysis. A symbol should only be shaded if the person, pregnancy, miscarriage, or abortion is clinically affected. Of course, whether a person is considered

affected may be a function of the sensitivity of the clinical tool that is used to define



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