Israel Medical Association Journal

Background: Long QT syndrome is an inherited cardiac disease, associated with malignant arrhythmias and sudden cardiac death.

Objectives: To map and identify the gene responsible for LQTS[1] in an Israeli family.

Methods: A large family was screened for LQTS after one of them was successfully resuscitated from ventricular fibrillation. The DNA was examined for suspicious loci by whole genome screening and the coding region of the LQT2 gene was sequenced.

Results: Nine family members, 6 males and 3 females, age (median and interquartile range) 26 years (13, 46), who were characterized by a unique T wave pattern were diagnosed as carrying the mutant gene. The LQTS-causing gene was mapped to chromosome 7 with the A614V mutation. All of the affected members in the family were correctly identified by electrocardiogram. Corrected QT duration was inversely associated with age in the affected family members and decreased with age.
Conclusions: Careful inspection of the ECG can correctly identify LQTS in some families. Genetic analysis is needed to confirm the diagnosis and enable the correct therapy in this disease

Background: Dedicated, organ-specific screening clinics have been shown to significantly reduce cancer morbidity and mortality.

Objectives: To establish a dedicated clinic for Clalit Health Service patients at high risk for hereditary gastrointestinal cancer and to provide them with clinical and genetic counseling, diagnostic screening and follow–up.

Results: During the 3 years of the clinic's activity, 634 high risk families, including 3804 at-risk relatives, were evaluated. The most common conditions were hereditary colorectal syndromes, Lynch syndrome (n=259), undefined young-onset or familial colorectal cancer (n=214), familial adenomatous polyposis (n=55), and others (n=106). They entered follow-up protocols and 52 underwent surgical procedures.

Conclusions: Consistent public and professional education is needed to increase awareness of hereditary colorectal cancer and the possibility of family screening, early diagnosis and therapy. The public health services – i.e., the four health management organizations – should provide genetic testing for these patients who, at present, are required to pay for almost all of these available but costly tests. Dedicated colorectal surgical units are needed to provide the specialized therapeutic procedures needed by patients with familial colorectal cancer. Our future plans include adding psychosocial support for these at-risk patients and their families as well as preventive lifestyle and dietary intervention. 

For centuries skin pigmentation has played a major societal role. Genetic disorders of skin pigmentation have therefore always evoked the curiosity of both laypersons and physicians. Normal skin pigmentation is a complex process that begins with the synthesis of melanin within the melanocytes, followed by its transfer to neighboring keratinocytes where it is translocated to the upper pole of the nucleus and degraded as the keratinocyte undergoes terminal differentiation. Mutations in various genes involved in melanocyte migration during embryogenesis, melanin synthesis and melanosomal function and transfer have been shown to cause pigmentation disorders. In the present review, we discuss normal skin pigmentation and the genetic underpinning of selected disorders of hypo- and hyperpigmentation.

Background: The C677T mutation in the methylenetetrahydrofolate reductase (MTHFR) gene is associated with early onset of coronary artery disease in some populations with certain ethnic backgrounds. However, data on its effect on CAD[1] development in women are limited and conflicting.

Objectives: To investigate the effects of the MTHFR C677T mutation and ethnicity on the development and age at onset of CAD in women in Israel.

Methods: The sample included 135 Jewish women with well-documented CAD (62 Ashkenazi, 44 Oriental and 29 of other origins) in whom CAD symptoms first developed at age ≤ 65 years. DNA samples from 235 women served as the control.

Results: CAD symptoms developed later in Ashkenazi than in Oriental women or women of other origins (51.0 ± 7.0 years vs. 48.3 ± 7.5 and 46.3 ± 7.7 years, respectively, P = 0.024). Among Ashkenazi women, the T/T genotype was less common in patients in whom CAD symptoms appeared after age 50 (6.4%) than in patients with earlier CAD symptoms (25.8%, P = 0.037) and Ashkenazi control subjects (23.3%, P = 0.045). Among women from other origins, these differences were not significant. On logistic regression analysis, the T/T genotype was associated with a nearly fourfold increase in the risk of early onset (age < 50 years) of CAD (odds ratio 3.87, 95% confidence interval 1.12–13.45, adjusted for risk factors and origin) and a trend towards an influence of ethnicity (P = 0.08). Compared to Ashkenazi women, the risk of early development of CAD associated with the T/T genotype among Oriental ones was 0.46 (95%CI[2] 0.189–1.114) and in women of other origins, 5.84 (95%CI 1.76–19.34). Each additional risk factor increased the risk of earlier onset of CAD by 42% (OR[3] 1.42, 95%CI 1.06–1.89).

Conclusions: The age at onset of CAD in Israeli women is influenced by the MTHFR genotype, ethnic origin and coronary risk factors.

Background: The contribution of the abnormal DNA mismatch repair system to non-small cell lung cancer tumorigenesis is controversial and has not been reported in Jewish Israeli patients. Similarly, the involvement of 3p deletions in NSCLC[1] in the same population has not been assessed.

Objectives: To assess the contribution of the DNA-MMR[2] system to NSCLC pathogenesis by analyzing microsatellite instability, and evaluate loss of heterozygosity at 3p rates in Israeli NSCLC patients.

Methods: Paired DNA from tumorous and non-tumorous tissue was extracted, and genotyping for MSI[3] determination was carried out using the five Bethesda markers and for determining LOH[4] two 3p markers were used. Genotyping was performed using polymerase chain reaction amplification and size separation on an ABI semiautomatic DNA sequencer, and the allelic patterns of tumorous and non-tumorous tissue were compared.

Results: Forty-four NSCLCs from 35 smokers and 9 non-smokers were analyzed, with 26 of the 44 (59%) at stage I disease. Using five microsatellite markers (D17S250, D5S346, D2S123, BAT-25, BAT-26) (known as Bethesda markers) for MSI determination, 6 of the 44 tumors (13.6%) exhibited MSI in at least one marker. Similarly, genotyping for LOH at chromosome 3p was performed using two markers (D3S4103, D3S1234) located at 3p14.2 l. With D3S4103, 33 of the 44 patients successfully analyzed were homozygous and therefore non-informative with respect to LOH. Using D3S1234, 33 of 36 patients (91.7%) were heterozygous, and 23 of these individuals' tumors (69.7%) displayed LOH. Unexpectedly, 4 of 33 tumors (12.1%) genotyped by D3S4103, and 16 of 36 tumors (44.5%) genotyped by D3S1234 showed a pattern of MSI, even though only one of these tumors showed a similar pattern when genotyped with the five consensus markers. Overall, 23 of 44 tumors (52.3%) demonstrated MSI on at least one marker, and 5 of these 23 tumors (21.7%) had MSI on two or more markers.

Conclusions: MSI using 3p markers and not the Bethesda markers occurs at a high rate and in early stages in Jewish NSCLC patients.