Genetic Disorders

Down Syndrome (also known as Trisomy 21)

A person with Down Syndrome has 3 chromosomes on #21. The mom’s egg has an extra chromosome. There are 2 types of Down Syndrome:

• MM1 – Mutation of mom’s egg occurs while mom was developing
• MM2 – Mutation of mom’s egg occurs as mom ages. Under age 30, chances of Down Syndrome are less than 1 in 1000. Over age 50, the chances are 1 in 12. The only option is prenatal testing, or in vitro fertilization.

Phenylketonuria (PKU)

A person with Phenylketonuria cannot break down phenylalnine because they do  not produce an enzyme. Phenylalnine is used in artificial sweeter, and found in diet sodas. When excess phenylalnine builds up, it causes mental retardation. There are strict dietary restrictions (low protien diet & Phenyl-free milkshare mix) for protein replacement).  Most critical time to monitor is before age 30.

Fragile X Syndrome

• More common in males
• Facial features
• Associated with hyperactivity, and attention deficit disorder

Exposure Disorders

Spina Bifida

• Occurs due to maternal lack of folic acid
• Neural tube does not close (day 23)
• Severity depends on opening size. Severe can lead to paralysis, limb deformity, and mental retardation
• Some forms may be genetic

Fetal Alcohol Syndrome

• Physical abnormalities: wide eyes, flat bridge of nose, longer space from from nose to lips with no ridge, thin upper lip
• Mental retardation
• The more you drink, the more likely fetal alcohol syndrome will occur