Multifactorial Inheritance

Sometimes many factors can result in a birth defect. For instance, genes from one or both parents may interact with each other and may be interfered with by environmental factors, usually unidentifiable. Birth defects caused in this way are poorly understood.

Conditions thought to result from multifactorial inheritance (when not part of a known syndrome) include:

• Cleft lip and cleft palate: malformations of the mouth
• Clubfoot: deformities of the ankle or foot
• Many congenital heart defects
• Diabetes mellitus: abnormal sugar metabolism, which usually appears later in life
• Certain forms of cancer
• High blood pressure
• Various malformations of the genital and urinary tract
• Certain malformations of the brain and spinal cord