Fig. 1: Drawing the patient's (P) pedigree. Note: 1. The slash in the relationship line indicates either divorce or separation. 2. This symbol indicates 4 siblings of unspecified sex. 3. The double line indicates consanguinity (in this case first cousins). 4. These siblings are monozygous twins. Dizygous twins are not joined by a horizontal line. If the type of twinning is unknown, a “?” replaces the horizontal line. 5. No children by choice or the reason is not known. 6. Infertility, indicate the reason if known. 7. Adopted into family. Children adopted out are drawn with a solid line of descent.
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