June 6, 2010
Persian Jews and Genetic Diseases
Persian Jewry is one of the oldest continuous Jewish communities in the world, having been isolated reproductively from other Jews, as well as other Iranians. Most now live in Israel and the United States, but before the Revolution, 150,000 Jews lived in Iran.
Because of the large Persian community in Los Angeles, Dr. David Rimoin, Director of the Cedars-Sinai Persian Jewish Genetic Screening Program, launched his center in 2009 to detect genetic diseases in this community. Recent advances allowed scientists to identify new markers for recessive genetic disorders in Persian Jews.
David Rimoin, M.D., Ph.D. is a professor at UCLA and a world-renowned genetics scholar. In 1971, he was part of the team that pioneered the first population-based screening program for Ashkenazi Jewish carriers of Tay-Sachs disease. I recently had the privilege of interviewing my esteemed UCLA colleague.
Dr. Lavin: Which disorders are most common in the Persian Jewish community?
Dr. Rimoin: There are four that we screen for at Cedars-Sinai.
(1) Pseudocholinesterase Deficiency causes sensitivity to certain forms of anesthesia, as well as other drugs. It is an inherited blood plasma enzyme abnormality, which should be made known to the anesthesiologist if you are undergoing surgery. When the anesthesiologist administers anesthesia to a patient with pseudocholinesterase deficiency, the patient experiences prolonged respiratory muscle paralysis, requiring mechanical ventilation to save the person’s life. By knowing in advance, safe drugs are selected and the paralysis will not occur. One in ten Persian Jews are carriers for anesthesia sensitivity. In one of 100 couples, both partners will be carriers; therefore 25% of their children may have the disorder.
(2) Congenital Hypoaldosteronism, (a salt-losing disorder) is a rare inherited disorder transmitted as either an autosomal recessive or autosomal trait with mixed penetrance. It is further subdivided into two types (CMO I and CMO II). Aldosterone is a hormone produced in the adrenal gland, which is important for sodium conservation. The clinical presentation of aldosterone deficiency is low sodium, high potassium, and acidosis, accompanied by short stature. Infants often are dehydrated and fail to thrive, but adults usually have no symptoms. Treatment is replacement of the absent hormone. One in 30 Persian Jews are carriers, and one in 900 Persian Jewish couples are at risk of having a child with this disorder.
(3) Autoimmune Polyendocrine Hormone Deficiency. In this condition, several hormones are deficient, but there are three main components, including: (a) a low parathyroid hormone resulting in very low calcium levels, (b) adrenal insufficiency (Addison’s Disease), which causes many symptoms including low blood pressure and weakness and (c) infection with Candida ( a yeast or fungal infection). Additional components may include Diabetes Mellitus Type I, low reproductive hormones, pernicious anemia, alopecia, and/or vitiligo. The frequency in Iranian Jews is 1 per 9,000. One in 50 Persian Jews are carriers.
(4) Hereditary Inclusion Body Myopathy is a progressive muscle disease characterized by muscle weakness developing in adults and is known as type IBM2 (autosomal recessive) in Persian Jews. It does not affect the brain or internal organs. Biopsies of the muscles in these patients reveal vacuoles with inclusions. Additional diagnostic tests include a sample of blood for creatinine kinase as well as nerve conduction studies. An MRI is helpful to determine sparing of the quadriceps and genetic testing confirms the diagnosis. Treatment is palliative – not curative. One in 20 Persian Jews are carriers, and one in 400 couples are at-risk of having a child with this condition.
Dr. Lavin: How often do these disorders occur?
Dr. Rimoin: They are as common in the Persian Jewish community as Tay-Sachs is to the Ashkenazi Jews. The carrier frequency (the possibility that someone will have one affected gene) for the four diseases ranges from 1:10 for pseudocholinesterase to 1:50 for autosomal polyglandular syndrome.
Dr. Lavin: Can we help these patients?
Dr. Rimoin: Yes. (1) For salt-losing Congenital Hypoaldosteronism, medication is readily available. (2) Autosomal Polyglandular Deficiency can also be treated with replacement hormones. (3) Patients with Pseudocholinesterase Deficiency can be easily managed during surgery, but the anesthesiologist must be made aware of this condition. (4) Unfortunately, for Hereditary Inclusion Body Myopathy, there is no cure at the present time, but preconception genetic counseling or prenatal diagnosis is available for couples in which both partners carry the mutated gene.
Dr. Lavin: Where do patients go for help?
Dr. Rimoin: The Medical Genetics Institute at Cedars-Sinai Medical Center is available to all Persian Jews. Simply contact my Center for further information.
Dr. Lavin: Besides these four diseases, are there others that testing is available for in this community?
Dr. Rimoin: Yes. We can also test for (1) Wolman disease – an untreatable illness (lipid storage disorder), which usually results in death in the first year of life and (2) Usher type II – an untreatable illness that causes deafness and poor vision.
Dr. Lavin: Should all Persian Jews be tested?
Dr. Rimoin: Yes, the program is not only for prenatal couples, but it is for every Persian Jew.
Dr. Lavin: What is the cost for testing?
Dr. Rimoin: Approximately $350 for all four tests, and if positive, we will provide genetic counseling.
Dr. Lavin: My colleagues and I applaud your compassion for the Persian Jewish Community as witnessed by the Cedars-Sinai Screening Program for these four diseases.
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