The results of a recent research study performed in collaboration with Rambam Health Care Campus (Rambam) in Haifa, Israel, revealed a high prevalence of colorectal cancer in Northern Israel among Arab and Druze communities, both of which have a high percentage of consanguineous marriages.
Marriages to first cousins and others with a close parental genetic relationship – known as consanguineous marriages – have been known to carry certain health risks for their descendants. Now, a recently published collaborative study with Rambam has found a new health risk for members of the Arab and Druze communities where consanguinity is particularly common. These individuals have been shown to be at high risk for developing colorectal cancer due to hereditary polyposis syndrome, a condition with an increased risk of developing polyps – benign or pre-cancerous growths found mostly in the colon or the rectum.
The study was performed by researchers from leading genetics institutes, hospitals, and universities in Israel, together with several of Rambam’s clinician-scientists. The study was led by Dr. Elizabeth Half, director of the Unit for the Detection and Prevention of Gastrointestinal Malignancies and of the Multidisciplinary Center for Early Detection and Prevention of Cancer at Rambam together with Gili Reznik-Levi, a genetic counselor from Rambam’s Genetics Institute. Other key researchers included Hanna Segev, head of Preimplantation Genetic Diagnosis at Rambam, Dr. Itay Maza, attending physician in the Genetics Institute and the principal investigator at the Maza Laboratory of the Clinical Research Institute at Rambam (CRIR), Dr. Yuri Gorelik, resident physician, and Dr. Karin Weiss, director of the Genetics Institute and principal investigator of the CRIR Weiss Laboratory.
Half comments, “Colon cancer begins with polyps that develop in the colon. Gastroenterological follow-up and colonoscopy tests make it possible to detect polyps in the pre-cancerous stage and, if possible, remove them. If not possible, the patient is referred for surgery to prevent cancer development. These processes translate into saving a high percentage of lives.”
Reznik-Levi explains that ten to twenty percent of colon cancer cases are hereditary. In these cases, the body’s MUTYH gene (one from the mother and one from the father) is mutated due to consanguinity.
“The syndrome accounts for about six percent of colon cancer cases at an early age,” Dr. Weiss adds, “It is well-known among the medical community that mutations in this gene are common in the European population and in Israel’s Jewish population with North African origins.”
Prior to this study, no research had been performed among Israel’s Arab population. The new study’s findings have now shown that the mutations found in consanguineous families differ from those in the general population, as well as from Israel’s Jewish population. It was also noted that the incidence of colon cancer in the younger population was higher. The average age for colon cancer onset in these families is 38 years, considerably lower than in others.
The results also showed that the risk of developing colon cancer can be avoided if regular colonoscopy examinations are initiated at a young age – between 20–25 years.
The next step of the research will be to look at the prevalence of MUTYH among healthy individuals in some villages in the Galilee region of Northern Israel. If the prevalence is high, it may be appropriate to offer genetic testing to the entire adult population in these villages.
The research team concluded, “It is important for us to be aware of this syndrome in the at-risk Arab and Druze populations of the Galilee. The general practitioners and gastroenterologists tasked with following the warning signs must refer the relevant patients to genetic counseling for early detection and even cancer prevention.”
Based on an article that first appeared in the Jerusalem Post, online edition.