Jewish Genetic Disease Awareness

JFCS is partnered with one of the world’s foremost biotechnology companies, Genzyme,
to raise awareness for all Jewish genetic diseases.

Approximately one in four people in the Ashkenazi Jewish population is a carrier of a Jewish genetic disease. If two carriers of the same condition have children together, there is a 25% chance with each pregnancy that their child will be born with the disease. There are more than a dozen inherited diseases that are common in the Jewish population. Some, such as Tay-Sachs disease, Dysautonomia, and Canavan disease, can lead to the early death of a child, while others such as Gaucher disease can be treated so the individual can lead a normal life. Early detection is key. JFCS, together with Genzyme, is committed to educating and informing the community about Jewish genetic diseases and disorders.

What Are the Disorders?

The following are descriptions of the 11 most common diseases, in order of carrier frequency, courtesy of Genzyme.

Type 1 Gaucher disease² – Carrier frequency: 1 in 15

Gaucher disease is an inherited disorder in which a fatty substance builds up in the body, especially in the spleen, liver, and bone marrow, and secondarily in the lungs, kidneys, and intestines.  Children or adults may have bruising, fatigue, anemia, nosebleeds, fractures, and enlargement of the liver and spleen.  Treatment options are available for Type 1 Gaucher disease.

Cystic Fibrosis (CF)³ – Carrier frequency: 1 in 26

CF is a disorder of unusually thick, sticky mucus production, primarily affecting the lungs and digestive system.  Most individuals with CF require lifelong medical care and experience reduced life expectancy.

Tay-Sachs disease⁴ – Carrier frequency: 1 in 30

Tay-Sachs disease is the best-known Jewish genetic disorder and is caused by a deficiency of an enzyme called hexosaminidase A (or hex A).  Lack of this enzyme affects the brain and the nervous system, causing rapid and progressive deterioration, with death usually occurring by the age of 6.  Babies with Tay-Sachs disease begin to lose developmental skills at 3 to 6 months of age.

Familial Dysautonomia (FD)⁵ – Carrier frequency: 1 in 30

FD is a nervous system disorder that commonly includes pain insensitivity, vomiting and sweating episodes, inability to produce overflow of tears, and unstable blood pressure or temperature.  Intelligence is often normal, but learning disabilities are common.  Symptom management improves quality of life, but only 50% will reach 30 years of age.

Canavan disease⁶ – Carrier frequency: 1 in 57

Canavan disease is a rare and devastating childhood nervous system disorder.  Canavan affects the formation of myelin, or white matter of the brain.  Symptoms usually occur within the first few months of life and the disease is fatal in early childhood.

Glycogen Storage Disorder Type 1a (GSD 1a)⁷ – Carrier frequency: 1 in 71*

GSD 1a is a disorder that, if untreated, results in severely low blood sugar, enlarged liver, growth retardation, and bleeding disorders.  Treatment consists of strict diet and continuous tube feeding of glucose (sugar).

Maple Syrup Urine disease (MSUD)⁸ – Carrier frequency: 1 in 81

MSUD is a disorder that leads to the buildup of branched-chain amino acids in the blood.  Without treatment, classic MSUD results in mental retardation, physical disabilities, coma, and death.  Treatment requires dietary restriction of branched-chain amino acids through a special medical formula and intensive monitoring.

Fanconi Anemia Type C⁹ – Carrier frequency: 1 in 89

An inherited anemia sometimes accompanied by short stature, skeletal defects, and skin abnormalities.  Learning disabilities or mental retardation sometimes occur.  The risk of early childhood cancer, especially leukemia, is increased.  There is currently no treatment.

Niemann-Pick disease Type A¹⁰ – Carrier frequency: 1 in 90

Niemann-Pick disease type A is a severe brain and spinal cord disorder in infants.  Affected babies experience feeding difficulty, recurrent vomiting, and enlargement of the spleen and liver, which causes the abdomen to appear distended by 6 months of age.  There is currently no treatment, and death occurs by 4 years of age.

Bloom’s Syndrome¹¹ – Carrier frequency: 1 in 100

Bloom’s Syndrome is a disorder characterized by poor growth, sun sensitivity, and high susceptibility to cancer.  Death from cancer usually occurs before 30 years of age.  Intelligence is normal.  There is currently no treatment.

Mucolipidosis Type IV (ML4)³ – Carrier frequency: 1 in 122

ML4 is a disorder characterized by severe neurological and eye abnormalities.  It usually appears within the first year of life and affected individuals reach the development age of 1 to 2 years.  There is currently no treatment.

Inheriting the Disorders

The following information is courtesy of Genzyme.

How are genetic disorders passed from one generation to the next?

Every person has two copies of a gene, one inherited from each parent.  These genes may be normal, or may contain defects that are known to cause genetic disorders.  For the disorders described here, an individual must have two copies of the defective gene in order to have the disorder.  These are called autosomal recessive genetic disorders.

What is a carrier?

A carrier is a person who has one normal copy of a gene and one defective copy.  Having one normal gene is enough to prevent the disorder.  Therefore, a carrier of a genetic disorder does not have any symptoms of the disorder.

However, if both parents are carriers of the same defective gene, there is a chance that each parent will pass his/her defective gene to their baby.  If the baby inherits two copies of the defective gene, the baby will have the disorder.  Couples may decide to have carrier testing to find out if they are carriers, and therefore are at risk of having a baby with one of these genetic disorders.

What if only one partner in a couple is Jewish?

If only one partner in a couple is Jewish, it is usual to test that person first.  If he or she is found to be a carrier of one of these disorders, the non-Jewish partner could then be tested.  However, if a pregnancy is already underway, it may be better to test both partners at the same time.

Are there prenatal tests for these disorders?

Yes.  If both parents are carriers of the same disorder gene, a prenatal diagnosis can be performed to determine whether or or not the fetus is affected.

Protect Your Loves Ones

• The only way to find out if you’re a carrier and at risk to have a child with a genetic disorder is by carrier screening through mutation analysis.
• Carrier screening is usually a simply blood test.
• A genetic counselor can help you decide if carrier screening is appropriate for you and can explain the benefits and limitations of the screening process.

Knowledge Is Power

You have the power to make an informed decision regarding having a child who could have a potentially serious genetic disorder.