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: 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: 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: The measurement of maternal serum human chorionic gonadotropin as a predictor of fetuses with Down syndrome has been in use since 1987.

Objectives: To determine the correlation between extremely high levels of hCG[1] at mid-gestation and maternal and fetal complications.

Methods: The study group consisted of 75 pregnant women with isolated high levels of hCG (> 4 MOM) at mid-gestation, and the control group comprised 75 randomly selected women with normal hCG levels (as well as normal alpha-fetoprotein and unconjugated estriol levels). The data collected included demographic details, fetal anomalies, chromosomal aberrations, pregnancy complications, and results of neonatal tests.

Results: There was a significant increase in the frequency of fetal anomalies (detected by ultrasound), low birth weight and neonatal complications in the study group. We also found an increased rate of fetal/neonatal loss proportional to the increasing levels of hCG (up to 30% in levels exceeding 7 MOM).

Conclusion: Our study demonstrated an increased frequency of obstetric complications that was closely associated with raised hCG levels. The study also raises questions about the accuracy of the Down syndrome probability equation in the presence of extremely high levels of hCG where data on the frequency of Down syndrome is severely limited.

Background: Transcobalamin II is a serum transport protein for vitamin B₁₂. Small variations in TC-II[1] affinity were recently linked to a high homocysteine level and increased frequency of neural tube defects. Complete absence of TC-II or total functional abnormality causes tissue vitamin B₁₂ deficiency resulting in a severe disease with megaloblastic anemia and immunologic and intestinal abnormalities in the first months of life. This condition was described in hereditary autosomal-recessive form. Low serum TC-II without any symptoms or clinical significance was noted in relatives of affected homozygotes.

Objectives: To study 23 members of a four-generation family with hereditary vitamin B₁₂ deficiency and neurologic disorders.

Methods: Thorough neurologic, hematologic and family studies were supplemented by transcobalamin studies in 20 family members.

Results: Partial TC-II deficiency was found in 19 subjects. Apo TC- II (free TC-II unbound to vitamin B₁₂) and total unsaturated B₁₂ binding capacity were low in all tested individuals but one, and holo TC-II (TC-II bound by vitamin B₁₂) was low in all family members. The presentation of the disease was chronic rather than acute. Early signs in children and young adults were dyslexia, decreased IQ, vertigo, plantar clonus and personality disorders. Interestingly, affected children and young adults had normal or slightly decreased serum vitamin B₁₂ levels but were not anemic. Low serum B₁₂ levels were measured in early adulthood. In mid-late adulthood megaloblastic anemia and subacute combined degeneration of the spinal cord were diagnosed. Treatment with B₁₂ injections resulted in a significant improvement. The pedigree is compatible with an autosomal-dominant transmission. This family study suggests a genetic heterogeneity of TC-II deficiency.

Conclusions: We report the first family with a hereditary transmitted condition of low serum TC-II (partial TC-II deficiency) associated with neurologic and mental manifestations in childhood. Partial TC-II deficiency may decrease the amount of stored cobalamin, resulting in increased susceptibility to impaired intestinal delivery of cobalamin and predisposing to clinically expressed megaloblastic anemia at a later age. Partial TC-II deficiency should be suspected in families with megaloblastic anemia and in individuals with neurologic and mental disturbances – despite normal serum vitamin B₁₂ levels. Low serum UBBC[2] and apo TC-II should confirm the diagnosis. Early vitamin B₁₂ therapy may prevent irreversible neurologic damage.

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.

Background: Achondroplasia is the most frequent form of disproportionate short stature, characterized by rhizomelic shortening of the limbs. This disorder is inherited as an autosomal dominant trait, although most of the cases are sporadic, a result of a de novo mutation. A recurrent glycine to arginine mutation at codon 380 (G380R) in the transmembrane domain of the fibroblast growth factor receptor 3 gene was found to cause achondroplasia among different populations. This is most uncommon in other autosomal dominant genetic diseases.

Objectives: To determine whether this mutation is also common among Jewish patients from diverse ethnic groups and among the Arab population in Israel.

Methods: We examined the G380R mutation (G>A and G>C transition) and the mutation G375C (G>T transition at codon 375) in 31 sporadic patients and in one family diagnosed clinically to have achondroplasia.

Results: We found the G>A transition at codon 380 in 30 of our patients and the G>C transition in one patient. We were not able to detect any of the three mutations in two patients with an atypical form of achondroplasia.

Conclusions: Our results further support the unusual observation that nucleotide 1138 of the FGFR3 gene is the most mutable nucleotide discovered to date across different populations.

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FGFR3 = fibroblast growth factor receptor 3

Background: In trials comparing different formulations of measles vaccine, excess non-specific mortality occurred in female children who received high titer vaccine. These findings suggest a gender-specific effect of measles vaccine.

Objectives: To determine whether gender differences exist in the rates of adverse reactions and morbidity in the month following immunization with measles-containing vaccine, and to evaluate whether there is a gender-specific association between the humoral immune response to measles vaccination and post-vaccination morbidity.

Methods: Parents completed questionnaires on the health status of 755 infants aged 15-20 months, during the month preceding and the month following the measles-mumps-rubella vaccination. Blood samples were tested for measles antibody titers in a subsample of 237 infants.

Results: After controlling background morbidity in the infants, the relative risk of fever and rash following vaccination was 2.35 in females and 1.36 in males. The geometric mean antibody titers against measles were similar in both sexes and there was no significant association between antibody titer and post-vaccination morbidity in either sex.

Conclusions: Our findings demonstrate higher rates of adverse effects in females following vaccination with MMR vaccine, irrespective of the humoral response. This study emphasizes the need to consider possible gender differences when evaluating new vaccines.

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MMR= measles-mumps-rubella

Background: Cystic fibrosis is the most common life-limiting autosomal recessive genetic disorder in Caucasians. Typically it is a multisystem disease diagnosed by increased chloride levels on sweat testing, with mortality due mainly to progressive respiratory disease. The clinical spectrum of CF has recently been much expanded.

Genetic testing for mutant CF transmembrane regulator has revealed atypical cases where sweat test results are borderline or normal. In other patients, genetic mutations cannot be identified but abnormal CFTR function is shown using nasal potential difference measurement.

Objectives: To highlight the diagnostic and therapeutic dilemmas in cases of atypical cystic fibrosis.

Methods: We reviewed patients with atypical CF and widely varying phenotype who are managed at Schneider Children’s Medical Center of Israel. 

Results: Two patients had severe lung disease but little expression in other organs. Accurate diagnosis was essential to enable aggressive therapy in a specialized center. Four other patients are in excellent general health but have symptoms limited to male infertility, heat exhaustion, pancreatitis or transient liver dysfunction, while lung disease is minimal. For these patients, careful counseling is needed to avoid unnecessary upheaval, inappropriately aggressive management, and the psychosocial implications of a CF diagnosis. These dilemmas have increased considerably in our center, as in others worldwide.

Conclusion: It is our obligation as clinicians - at the level of both primary physician and referral center - to maintain an ever higher index of suspicion for CF, tempered by a rational program of counseling and management appropriate to the individual.

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CF= cystic fibrosis

CFTR= CF transmembrane regulator

Background: Hypertension is one of the most prevalent vascular diseases in the adult population. It is an important determinant of atherosclerosis in adolescents and young adults. There is to date no information on blood pressure in children of the Israeli Arab population.

Objectives: To study blood pressure in Israeli Arab children and adolescents.

Methods: Blood pressure measurements were taken in the supine position in 4,488 Israeli Arab children and adolescents of both sexes aged 6–17 years. Height and weight were also determined. Correlation was investigated between systolic and diastolic blood pressure, body mass index, gender, and age.

Results: The systolic and diastolic blood pressures were similar in both sexes for all age groups up to 14 years of age. Systolic blood pressure was significantly (P<0.001) higher in males aged 15–17 years  (120±13 vs. 111±12 mmHg, 123±13 vs. 113±14.0 mmHg, and 123±18 vs. 111±14 mmHg, respectively). Diastolic blood pressure was higher in males aged 15–17, with a statistically significant difference for age 17 only (75±12 vs. 69±13 mmHg). Blood pressure was elevated in 322 students in the initial screening (7.17%), with a decrease to 2.18% when this group was rescreened 2 weeks later. The systolic blood pressure in our group is higher than that in Jewish Israeli children of Asian and North African origin, and in American children. It is similar to the systolic blood pressure of European children and Jewish children born in Israel. The diastolic blood pressure in our group is higher than that in all groups of Israeli Jewish children and American children of different ethnic groups.

Conclusions: Israeli Arab children and adolescents have higher blood pressure levels than their Israeli Jewish counterparts. Further studies are required to confirm this observation.