Israel Medical Association Journal

Background: Since the identification of the MEFV gene 198 mutations have been identified, not all of which are pathologic. The screening methods used in Israel to test patients suspected of having FMF include a kit that tests for the five main mutations (M694V, V726A, M680Ic/g, M694I, E148Q), and the sequencing of MEFV exon 10 in combination with restriction analysis for detecting additional mutations.

Objectives: To determine the contribution of testing for five additional mutations – A744S, K695R, M680Ic/t, R761H and P369S – to the molecular diagnosis of patients clinically suspected of having FMF.

Methods: A total of 1637 patients were tested for FMF mutations by sequencing exon 10 and performing restriction analysis for mutations E148Q and P369S.

Results: Nearly half the patients (812, 49.6%) did not have any detectable mutations, 581 (35.5%) had one mutation, 241 (14.7%) had two mutations, of whom 122 were homozygous and 119 compound heterozygous, and 3 had three mutations. Testing for the additional five mutations enabled us to identify 46 patients who would have been missed by the molecular diagnosis kit and 22 patients who would have been found to have only one mutation. Altogether, 4.3% of the patients would not have been diagnosed correctly by using only the kit that tests for the five main mutations.

Conclusions: This study suggests that testing for the additional five mutations as well as the five main mutations in patients with a clinical presentation of FMF adds significantly to the molecular diagnosis of FMF in the Israeli population.
 

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: Fanconi anemia complementation group C and Bloom syndrome, rare autosomal recessive disorders marked by chromosome instability, are especially prevalent in the Ashkenazi* Jewish community. A single predominant mutation for each has been reported in Ashkenazi Jews: c.711+4A→T (IVS4 +4 A→T) in FACC[1] and BLM^Ash in Bloom syndrome. Individuals affected by both syndromes are characterized by susceptibility for developing malignancies, and we questioned whether heterozygote carriers have a similarly increased risk.

Objectives: To estimate the cancer rate among FACC and BLM^Ash carriers and their families over three previous generations in unselected Ashkenazi Jewish individuals.

Methods: We studied 42 FACC carriers, 28 BLM^Ash carriers and 43 controls. The control subjects were Ashkenazi Jews participating in our prenatal genetic screening program who tested negative for FACC and BLM^Ash. All subjects filled out a questionnaire regarding their own and a three-generation family history of cancer. The prevalence rates of cancer among relatives of FACC, BLM^Ash and controls were computed and compared using the chi-square test.

Results: In 463 relatives of FACC carriers, 45 malignancies were reported (9.7%) including 10 breast (2.2%) and 13 colon cancers (2.8%). Among 326 relatives of BLM^Ash carriers there were 30 malignancies (9.2%) including 7 breast (2.1%) and 4 colon cancers (1.2%). Controls consisted of 503 family members with 63 reported malignancies (12.5%) including 11 breast (2.2%) and 11 colon cancers (2.2%).

Conclusions: We found no significantly increased prevalence of malignancies among carriers in at least three generations compared to the controls.

Background: Familial nephritis is a heterogeneous group of disorders caused by several genetic conditions such as Alport syndrome, glomerulonephritic syndromes, and unclas­sified nephritis without deafness or ocular defects.

Objectives: To describe a family of Iraqi Jewish origin, several of whose members suffer from non-syndromic renal failure without deafness or ocular defects and where transmis­sion is by autosomal dominant inheritance. We present the case histories of four family members and describe the molecular analysis performed in order to seek a possible linkage to one of the genes causing Alport or Alport-like syndromes.

Methods: We investigated all family members over the age of 18 for evidence of renal failure. We also extracted DNA and carried out molecular linkage analysis with polymorphic markers in each of the known loci involved in Alport and Alport­like syndromes.

Results: Histology of the renal biopsy specimens showed non-specific findings. Linkage was excluded for all the Alport and Alport-like syndrome loci.

Conclusions: The condition suffered by several members of this family seems to represent a unique autosomal dominant type of progressive hereditary nephritis, characterized by hypertension and progressive renal failure without significant hematuria or proteinuria. The main histological changes are non-specific in the early stage of the disease. Our study rules out all the currently known genes that cause Alport syndrome as being responsible for the basic defect in this type of nephritis.