Multifactorial inheritance
Disease Information
In-Depth
What are examples of multifactorial diseases and traits?
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Neural tube defects
- occur in one to two out of every 1,000 births
- five times more common in females than in males
- can be caused by environmental factors, diabetes in the mother and certain medications
- a couple having a second child with the defect is increased 3 to 5 percent
-
Hip dysplasia
- occurs in one in 1,000 births
- nine times more common in females than in males
- one environmental factor may be the baby's response to mother's hormones during pregnancy
- Cleft lip or palate (when not part of a known disorder)
- Type 2 diabetes
- Obesity
- Some forms of cancer
How do I know if my child is at risk for a trait or disorder seen in another family member?
The chance for a multifactorial trait or condition to happen in your child depends on how closely you are related to the family member with the trait (the closer the relative, the higher your child's risk). Family members share a certain percentage of genes in common, depending upon their relationship. For example:
| Degrees of relationship | Percentage of Genes in Common | Example |
|---|---|---|
| First Degree Relative | 50 percent | Parents, children, siblings |
| Second Degree Relative | 25 percent | Aunts, uncles, nieces, nephews, grandparents |
| Third Degree Relative | 12.5 percent | First cousins |
