Israel Medical Association Journal

Background: Reduced sensitivity to thyroid hormone (RSTH) syndrome describes a group of rare heterogeneous genetic disorders. Precise diagnosis is essential to avoid unnecessary treatment.

Objectives: To identify and characterize previously undiagnosed patients with RSTH in Israel.

Methods: Patients with suspected RSTH throughout Israel were referred for study. After clinical evaluation, genomic DNA was obtained and all coding exons of the thyroid hormone receptor beta (THRB) gene were sequenced. If mutations were found, all available blood relatives were evaluated. The common polymorphism rs2596623, a putative intronic regulatory variant, was also genotyped. Genotype/phenotype correlations were sought, and the effect of mutation status on pregnancy outcome was determined.

Results: Eight mutations (one novel; two de-novo, six dominant) were identified in eight probands and 13 family members. Clinical and genetic features were similar to those reported in other populations. Previous suggestions that rs2596623 predicts clinical features were not confirmed. There was no evidence of increased risk of miscarriage or fetal viability. Mothers carrying a THRB mutation tended to have increased gestational hypertension and low weight gain during pregnancy. Their affected offspring had increased risk of small-for-gestational age and poor postnatal weight gain.

Conclusions: Clinical heterogeneity due to THRB mutations cannot be explained by the variant rs2596623. Mothers and newborns with THRB mutations seem to be at increased risk of certain complications, such as gestational hypertension and poor intrauterine and postnatal growth. However, these issues are usually mild, suggesting that routine intervention to regulate thyroid hormone levels may not be warranted in these patients.

Background: Down syndrome is one of the most common chromosomal abnormalities. Children and adults with DS[1] have significant medical problems and require life-long medical follow-up.

Objectives: To determine the adequacy of medical surveillance of individuals with DS as recommended by the American Academy of Pediatrics.

Methods: The study was conducted at a multidisciplinary center specializing in the care of DS during the period 2004–2006. At their first visit to the Center, caregivers of individuals with DS were questioned about the medical status of their child including previous evaluations. Medical records brought in by the parents were reviewed.

Results: The caregivers of 150 individuals with DS (age ranging from newborn to 48 years old, median age 5 years) were interviewed and medical records were reviewed. The prevalence of specific medical problems differed between our population and the reported prevalence from other surveys. For example, 39.3% of our population had documented auditory deficits while the reported prevalence is 75%. For gastrointestinal and thyroid disease, the prevalence was higher in the studied population than that reported in the literature. In terms of compliance with the AAP[2] recommendations, most children (94%) underwent echocardiography, but only 42.7% and 63.3% had been tested for auditory or visual acuity respectively. Only 36.3% over the age of 3 years had cervical spine films.
Discussion: Many individuals with DS are not receiving appropriate medical follow-up and the implications of inadequate surveillance can be serious

The complex genetic nature of many common diseases makes the identification of the genes that predispose to these ailments a difficult task. In this review we discuss the elements that contribute to the complexity of polygenic diseases and describe an experimental strategy for disease-related gene discovery that attempts to overcome these factors. This strategy involves a population-based case-control paradigm and makes use of a highly informative, homogeneous founder population, many of whose members presently reside in Israel. The properties of single nucleotide polymorphisms, which are presently the markers of choice, are discussed, and the technologies that are currently available for SNP[1] genotyping are briefly presented.

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[1] SNP = single nucleotide polymorphism

Background: Familial Mediterranean fever is a genetic disease in which some characteristic gene mutation have been found.

Objective: To analyze the phenotype-genotype correlations in North African Jews and Armedians with FMF.

Methods: We studied MEFV gene mutations and phenotype-genotype correlations in North African Jews and Armedians with Familial Mediterranean Fever living in France.

Results: M694V mutation was the most common mutation in Jews and in Armenians. Patients with M6801 homozygosity or M6801/M694V compound heterozygosity had a phenotype as severe as patients with M694V homozygosity.

Conclusions: This study characterizes the phenotype-genotype in specific ethnic groups of patients with FMF.