Penn Ob/Gyn Care

Glossary of Prenatal Genetic Conditions

View a glossary of prenatal genetic conditions.

Bloom syndrome

Is characterized by short stature, sun-sensitive facial skin lesions, and an increased susceptibility to infections. Individuals have a higher incidence of leukemia and certain cancers. Approximately 1 in 100 Ashkenazi Jews is a carrier of this condition.

Canavan disease

Children with this condition develop normally until age two to four months, followed by progressive loss of previously attained skills. Most children with this disease die by the age of five. An estimated 1 in 40 Ashkenazi Jews is a carrier for this disease.

Cystic fibrosis

Is a serious, life-threatening disease in children. It affects various body systems by producing abnormally thick secretions that can obstruct the pancreas, intestines, bile ducts, and air passages in the lungs. The carrier rate among all Caucasian individuals is approximately 1 in 25.

Down syndrome

Also called "trisomy 21," occurs when there is an extra chromosome 21 present in cells of the fetus. A child with an extra chromosome 21 will have mental retardation and the characteristic appearance of Down syndrome. About 40 percent of children with Down syndrome are also born with serious heart problems. Down syndrome occurs in approximately 1 in 800 births. The older a woman is at the time of her delivery, the greater the chance that she will have a baby with Down syndrome.

Familial dysautonomia

A disease that causes the autonomic and sensory nervous systems to malfunction affecting the regulation of body temperature, blood pressure, stress response, normal swallowing and digestion. An estimated 1 in 30 Ashkenazi Jews is a carrier of this condition.

Fanconi anemia

A disease associated with short stature, bone marrow failure and a predisposition to leukemia and other cancers. Some children may have learning difficulties or mental retardation. Approximately 1 in 89 Ashkenazi Jews is a carrier for this condition.

Gaucher disease

A condition that varies in age of onset and in the progression of symptoms. The initial symptoms include a painful, enlarged and overactive spleen, anemia and low white blood cell count. Bone deterioration is a major cause of pain and disability. Approximately 1 in 14 Ashkenazi Jews is a carrier of this condition. Treatment is available.

Mucolipidosis IV

Is caused by the accumulation of specific harmful substances throughout the body. Individuals with this condition experience varying levels of motor and mental retardation, with developmental delays often manifesting themselves as early as the first year of life. Other symptoms can affect the eyes, such as corneal clouding, and retinal degeneration. Approximately 1 in 100 Ashkenazi Jews is a carrier of this condition.

Niemann-Pick disease

A condition in which a harmful amount of a fatty substance accumulates in different parts of the body. A progressive neurodegenerative disorder that leads to death by age 3. The carrier rate in the Ashkenazi Jewish population is approximately 1 in 90.

Neural tube defects: Spina bifida

Is a neural tube defect in which the bones of the spine do not completely form, and the spinal canal is incomplete. Anencephaly is a severe and usually fatal defect that occurs when the skull and brain fail to develop.

Sickle cell anemia

Occurs when an abnormal form of hemoglobin is produced. Instead of easily moving through the bloodstream, sickle cells can clog blood vessels and deprive the body's tissues and organs of the oxygen they need to stay healthy. Sickle cell disease affects 1 in 375 African-Americans and more than 1 in 50,000 Americans.

Tay-Sachs disease

Children with Tay-Sachs develop normally until about four to six months of age when the central nervous system begins to degenerate. Individuals with this condition lack an enzyme called hexosaminidase. The child loses all motor skills and becomes blind, deaf and unresponsive. Death usually occurs by the age 4. The carrier rate in the Ashkenazi Jewish population is approximately 1 in 25.

Trisomy 18 syndrome

Caused by the presence of an extra number 18 chromosome, which leads to multiple abnormalities. Many of these abnormalities make it hard for infants to live longer than a few months. Trisomy 18 syndrome occurs in approximately 1 in 6,000 live born infants.