Introduction

Questions and Answers

Inheritance Patterns

MDA's Search for a Cause

MDA's Search for a Treatment or Cure

INHERITANCE PATTERNS

In autosomal dominant disorders, a child need inherit only one abnormal gene to have the disease. The chance of a child inheriting this one abnormal gene is 50 percent with each conception.

X-linked diseases are caused by defects in genes on the X chromosome. Females have two Xs, and males have only one, paired with a Y chromosome.

In X-linked dominant diseases, an abnormal X chromosome gene from either parent can cause the disease. The chances of a child getting the disease is 50 percent if the mother has the defect on one of her Xs. If it's the father who has the defect (not shown), only girl children will inherit it, because boys get a Y chromosome from the father, not an X. All female children will inherit the defect, since they all get their father's sole X chromosome.

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