15 July 2010

IAJGS 2010: Persian Jewish genetic disorders

Monday's programming offered many Sephardic programs, and one session focused on Ashkenazi and Persian genetic diseases.

While Ashkenazi genetic diseases have been written about extensively, here's more on the less-well known Persian conditions.

Richard Gladstein, head of Jewish Genetics Disease Consortium, produced a very moving film on Jewish genetic conditions, focusing on families raising children with ML4, Tay-Sachs, Bloom's Syndrome and others. His child has Bloom's Syndrome.

The film demonstrates the importance of genetic screening before a couple plans a pregnancy. There are 16 common Ashkenazi recessive (both parents must be carriers). One in five Ashkenazi Jews is a carrier for at least one of those conditions.

For more information, go to the Jewish Genetic Disease Consortium site.

Dr. David Rimoin of Cedars-Sinai Hospital spoke on Persian hereditary genetic conditions, and he is head of Persian Jewish Genetics Screening at Cedars-Sinai Medical Center.

In 1970, he arrived in California and recruited Dr. Michael Kaback, who discovered enzyme screening for Tay-Sachs detection. The screening began in California and then throughout the Jewish world. The incidence of Tay-Sachs has been reduced by 90% through extensive community screening programs.

Rimoin believes it is now time - 40 years later - to wipe out other genetic conditions in certain communities.

He said that every community has some genetic conditions more prevalent than others.

Populations should be screened to see if they are carriers, or to find effected individuals and do something about it, "even though it is politically correct to ignore such things. All populations have common conditions."

Examples of some would be sickle cell anemia among blacks, or Tay-Sachs among Ashkenazi Jews. Similar conditions can be found in all populations but rates change for each population or mutations.

There are some Sephardic conditions such as Familial Mediterranean Fever and Machado Disease and there are some four conditions prevalent in the Persian community.

These are autosomal recessive disorders, which means both parents must be carriers to impact a child. If both parents are carriers, each fetus can be tested to see if it has the condition and the parents can decide what to do. Tests include amniocentesis at 16-18 weeks; chorionic villous sampling at 9-11 weeks; or pre-implantation genetic diagnosis in vitro to only implant healthy embryos.

Although Tay-Sachs has dropped by 90% among Jewish families, it is still found in non-Jewish families. With assimilation, people do not know their own backgrounds and the chance is higher. Screening is important for all as people do not know who they are.

Rimoin showed a Tay-Sachs incidence chart. The chance of it occurring in the USA general non-Jewish population is 1/300; Ashkenazi 1/29; Moroccan 1/110; Iraqi 1/140; French Canadians 1/30; Cajuns 1/30; and Irish 1/44. Note that the incidence among French Canadians and Cajuns is nearly the same as in Ashkenazi Jews. The question was asked of Rimoin if this indicates that those two populations may have Jewish ancestry, and the answer was yes.

He informed attendees that Ashkenazim were mainly in Eastern Europe, Sephardim have origins in Iberia (Spain and Portugal); and that Mizrahim are from the Middle East and North Africa. They also spoke Yiddish vs Ladino, and had completely different genetic conditions, likely due to isolation. Ashkenazim have 16 such conditions, Sephardim have many fewer, while Persians have four major ones.

Rimoin also stated that in Israel, there is only prenatal diagnosis, and what is recommended varies by origins of the couple. Ashkenazim are tested for 17, North Africans and Libyans a smaller number, Sephardic Moroccans and Iraqis for seven, Sephardic Yemenites for a few.

He provided a capsule of history for the Persian community, which is centered in Los Angeles and in New York.

Jews arrived in Iran during the Babylonian Exile, although some date from the earlier Assyrian Exile. Some returned to help rebuild the Temple in Jerusalem as allowed by Kourosh (Cyrus), while others remained in communities and intermarried among themselves with no contact with other Jews. During the Revolution, most came to Los Angeles, where there are some 70,000 - although it always seems a much larger community, a similar number in Israel and some 15,000 in New York.

In Iran, the community split from other communities some 2,500 years ago with little contact.

The four autosomal conditions are:

-- Anesthesia sensitivity disorder (pseudocholinesterase)

-- Salt-losing disorder (congential hypodosteronism)

-- Polyglandular multiple hormone deficiency

-- Hereditary Inclusion Body Myopathy (hereditary muscle disorder)

These can be diagnosed, treated, prevented or avoided.

The incidence and characteristics of each in the Persian community:

Anesthesia sensitivity: 1/10 carriers 1/100 are affected, 1/300 at-risk. Most don't know they have it. It can cause difficulty breathing or muscle weakness. Complications can be avoided through use of other drugs.

Congenital salt-losing disorder: 1/30 are carriers. It produces critical dehydration and shock in newborns. If untreated, may die. Less severe cases produce poor weight, short stature, blood pressure, weak, dizziness. normal lifespan and development with simple treatment and early diagnosis.

Polyglandular deficiency: 1/50 are carriers , 1/2,500 at risk. It causes skin infections, weakness, loss of appetite, hair loss, anxiety, depression, twitching muscles, some hair loss. It is easily treatable.

Hereditary Inclusion Body Myopathy: 1/20 are carriers. The hereditary muscle disorder produces progressive muscle weakness in arms and legs, beginning ages 20s-30s, with difficulty walking and gradual worsening. Most are severely debilitated and cannot walk. Prenatal diagnosis, in vitro, and it can be wiped out like Tay-Sachs.

Genetic testing is available. Rimoin arranged massive screenings in congregations and at the hospital, some 1,000 individuals were tested using saliva samples. Strict confidentiality was followed using genealogical questionnaire, bar codes, self-addressed envelopes. Each carrier was followed up and the affected were brought in. Only the individual or parents were informed. No one under age 16 was tested unless both parents were carriers. Family planning and prevention were discussed. They plan to extend this to other Persian Jewish communities and in Israel, and as a pilot for other communities with their own genetic conditions.

Tracing the Tribe asked Rimoin what the genealogical questionnaires revealed and whether it revealed if there was a higher incidence in some communities over others. He said that some 15 communities were listed but that results did not indicate which conditions were more prevalent in certain communities.

What the testing revealed:

--Anesthesia sensitivity: 9 people not affected, 121 carriers, at-risk couples 7

--Congential salt-losing disorder: 963 not affected, 28 carriers, 6 affected, at-risk couple 1

-- Polyglandualar: 37 carriers ....

I didn't have time to transcribe the rest of the chart flashed on the screen, but it showed also that 30% of those tested have one or more conditions and that 10 couples were at-risk.

Rimoin believes all Jewish Persian individuals should be tested.

Through the Persian genetic screening center, the cost is $350 for all four tests; normally, each test is $1,000. Saliva kits have been delivered to physicians all over the community. It is easy to get screening.

Rimoin has involved the community's Persian synagogue rabbis to include the screening in pre-wedding counseling.

For more information, contact the Jewish Genetic Diseases Consortium.

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