Down Syndrome Trisomy 21
Spina Bifida
Neural Tube Defects
Occurs 1-2 per 1000 births.  This birth defect results from incomplete closure of the neural tube.  This usually affects the nerves at the level of the defect.  The severity depends on the location and size of the defect, as well as the extent of nerve root involvement.  Hydrocephalus requiring a shunt often complicates spina bifida.
Cleft lip/palate A defect of the lip and/or palate.  Varies with type and severity.
Cystic fibrosis One of the most common genetic conditions. It causes chronic lung and intestinal problems, poor weight gain and other symptoms, usually beginning in early childhood. Although treatment for cystic fibrosis has improved, life span and quality of life remain limited.
Tay-Sachs Disease Occurs mainly in Ashkenazi Jews (ones of Eastern European descent). It is a disorder in which infants, who can appear normal at birth, develop degenerative neurologic problems and generally die by the age of five. No treatments are currently available.
Other Jewish related conditions Other genetic diseases more common among Ashkenazi Jews include Bloom Syndrome, Canava Syndrome,  Familial Dysautonomia, Fanconiís Anemia, Gaucher disease and Neiman-Pick (Type A).

Bloom syndrome results in individuals having many abnormalities including an increased susceptibility to cancer and leukemia. Some individuals with Bloom syndrome also have mental retardation. One in 100 Ashkenazi Jewish individuals is a carrier for Bloom syndrome.  

Canavan disease is caused by the lack of an enzyme in the body called aspartoacylase (ASPA).  Canavan disease may cause brain damage, a large head, tremors, blindness, feeding difficulties, poor weight gain, and problems with swallowing.  An estimated one in 40 Ashkenazi Jews is a carrier for Canavan disease.

Familial dysautonomia (FD) is an inherited disorder leading to problems with swallowing, temperature regulation, blood pressure regulation, feeding, and sensation to pain.   An estimated one in 30 Ashkenazi Jews is a carrier for FD.

Fanconi anemia in an inherited condition characterized by a reduced production of all types of blood cells.  Individuals with Fanconi anemia have many abnormalities including an increased risk for cancer and leukemia. An estimated one in 89 Ashkenazi Jews is a carrier for Fanconi anemia.

Gaucher disease is an inherited disorder caused by a change in the gene responsible for making an enzyme called glucocerebrosidase   This can cause a wide range of abnormalities including liver and bone abnormalities.  Type 1 Gaucher disease is the most common genetic disorder among Jews. An estimated one in 10 Ashkenazi Jews is a carrier for Gaucher disease.

Niemann-Pick disease (Type A) is caused by the lack of a substance called acid sphingomyelinase.  Individuals with Nieman-Pick have problems including developmental delay, progressive spasticity, blindness, an enlarged liver and/or spleen, and a "cherry-red spot" in the eye.   An estimated one in 100 Ashkenazi Jews is a carrier for Niemann-Pick disease.
Sickle cell disease An inherited disease of red blood cells which can cause attacks of pain, damage to vital organs, risk of serious infections and can lead to early death. Sickle cell disease affects the main protein inside the red blood cells called hemoglobin. The disease occurs when a person inherits one sickle cell gene from each parent or a combination of one sickle cell gene plus one of several other abnormal hemoglobin genes. One of the most serious complications of sickle cell anemia is stroke, a bleed or blockage of blood within the blood vessels of the brain. About 10 percent of children with sickle cell anemia have a stroke, which can lead to lasting disabilities, by age 20.
Most cases of sickle cell disease occur among African-Americans, and Hispanics of Caribbean ancestry. About one in every 400 African-Americans has sickle cell disease. It also affects people of Arabian, Greek, Maltese, Italian, Sardinian, Turkish and Indian ancestry.
Thalassemia Thalassemia consists of a group of inherited diseases of the blood. About 100,000 babies worldwide are born with severe forms of the disease each year. Thalassemia occurs most frequently in people of Italian, Greek, Middle Eastern, Southern Asian and African ancestry.

Thalassemia includes a number of different forms of anemia (red blood cell deficiency). The two main types are called alpha and beta thalassemias, depending on which part of an oxygen-carrying protein (called hemoglobin) is lacking in the red blood cells. The most severe form of alpha thalassemia, which affects mainly individuals of affects lacking in the red blood cells. The most severe form of alpha results in affects mainly individuals of Southeast Asian, Chinese and Filipino Southeast Asian, Chinese and Filipino ancestry, milder forms of the results in fetal or newborn death. Most individuals with alpha no effect on health.
milder forms of the disease, with varying degrees of anemia.  Individuals with no effect on health.beta thalassemias have variable symptoms ranging from very severe to having no effect on health.results in fetal or newborn death. Most individuals with alpha thalassemia have milder forms of the disease, with varying degrees of anemia.  Individuals with beta thalassemias have variable symptoms ranging from very severe to having no effect on health.

Thalassemia major, the most severe form, is also called Cooley's anemia, named after the doctor who first described it in 1925. Most children with t thalassemia major appear healthy at birth, but during the first year or two of life they become pale, listless and fussy, and have a poor appetite.  They grow slowly and often develop jaundice (yellowing of the skin).  Without treatment, the spleen, liver, and heart soon become greatly enlarged. Bones become thin and brittle; face bones become distorted, and children with thalassemia often look alike. Heart failure and infection are the leading causes of death among children with untreated thalassemia major.

Thalassemia intermedia is a mild Cooley's anemia. Children with thalassemia intermedia may develop some of the same complications, although in most cases, the course of the disease is mild for the first two decades of life.

Fragile X syndrome The most common inherited form of mental retardation, affecting about 1 in 4,000 males and 1 in 8,000 females (Down syndrome is the most common cause of mental retardation, occurring in about 1:700 birth, but it is rarely inherited).

Fragile X syndrome occurs in all racial and ethnic groups.  It is caused by an abnormality in a single gene of the "X" chromosome.  This is also one of the "sex" chromosomes (females have 2 X chromosomes while males have one X and one Y chromosome).  The mutation- (called FMR-1) - was discovered in 1991 and it can be tested for in families known to be at risk.  About one in 250 women in this country carries the fragile X gene. A woman is considered a carrier of fragile X syndrome if she has either a pre-mutation (60 to 200 trinucleotide repeats within her FMR-1 gene) or a full mutation (greater than 200 trinucleotide repeats within her FMR-1 gene). A carrier of a pre-mutation generally has no symptoms of fragile X syndrome, though recent studies suggest that women who carry this pre-mutation may be at increased risk of early menopause (prior to age 40). Approximately one-third to one-half of female carriers of a full mutation will exhibit signs of fragile X syndrome, but are usually less severely affected than males with full mutations.  Because the genetics of fragile X syndrome are complicated, a couple with a family history of fragile X syndrome should consult a medical geneticist or a genetic counselor to learn more about the risks of this disorder in their offspring.

Other Genetic Conditions Adrenoleukodystrophy
Gaucher Disease
Hirschsprung's Disease
Niemann-Pick Disease
von Hippel-Lindau