Biomedical subjects

L Horev

Publications and source records attributed to L Horev.

6 recordsLinked to original sources

PubMed2003

Identification of mutations in the COL7A1 gene in a proband with mild recessive dystrophic epidermolysis bullosa and aortic insufficiency.

We report the clinical and molecular findings in a patient with a mild form of recessive dystrophic epidermolysis bullosa and aortic insufficiency. To our knowledge, this is the first report of association between dystrophic epidermolysis bullosa and abnormalities of the aortic valve. Analysis of the COL7A1 gene has revealed two new mutations, a 20-bp duplication and a splice site mutation.

Adult↗

PubMed2003

Identification of a locus for type I punctate palmoplantar keratoderma on chromosome 15q22-q24.

BACKGROUND: The identification of the molecular basis of disorders of keratinisation has significantly advanced our understanding of skin biology, revealing new information on key structures in the skin, such as the intermediate filaments, desmosomes, and gap junctions. Among these disorders, there is an extraordinarily heterogeneous group known as palmoplantar keratodermas (PPK), for which only a few molecular defects have been described. A particular form of PPK, known as punctate PPK, has been described in a few large autosomal dominant pedigrees, but its genetic basis has yet to be identified. AIM: Identification of the gene for punctate PPK. METHODS: Clinical examination and linkage analysis in three families with punctate PPK. RESULTS: A genomewide scan was performed on an extended autosomal dominant pedigree, and linkage to chromosome 15q22-q24 was identified. With the addition of two new families with the same phenotype, we confirmed the mapping of the locus for punctate PPK to a 9.98 cM interval, flanked by markers D15S534 and D15S818 (maximum two point lod score of 4.93 at theta = 0 for marker D15S988). CONCLUSIONS: We report the clinical and genetic findings in three pedigrees with the punctate form of PPK. We have mapped a genetic locus for this phenotype to chromosome 15q22-q24, which indicates the identification of a new gene involved in skin integrity.

Chromosome Mapping↗

PubMed2001

Investigation of the threshold for allergic reactivity to chromium.

Allergy to chromium is relatively common, often in association with exposure to cement or in leather manufacture. However, in certain locations, there appears to be a relatively large cohort of chromium-sensitive individuals whose allergy cannot be explained by these common sources. In particular, this group include Israeli housewives with persistent hand eczema and concomitant patch test positivity to chromium. The causation of their allergy has been linked with relatively high levels of chromium contamination in household products. To provide further information in respect of the definition of safe levels for such products, we examined 17 chromium-allergic individuals to determine their threshold for reaction under closed patch test and repeated open application test (ROAT) conditions. The data derived indicated that, on normal skin, the patch test threshold was 10 ppm chromium; in the presence of an irritant (sodium lauryl sulfate) the threshold was closer to 1 ppm, 2/17 subjects giving 1+ reactions at this concentration. In the more realistic exposure conditions of the ROAT, 8/14 individuals failed to react to 50 ppm, whilst 3/15 reacted to 5 ppm. Interestingly, there was very poor correlation between patch test sensitivity and ROAT sensitivity. To ensure the large majority of chromium-allergic individuals do not suffer elicitation of their allergy, as well as to limit the development of new chromium-sensitive subjects, it is recommended that household products adhere to a previously published standard of a maximum limit of 5 ppm, with an ultimate target of 1 ppm contamination by chromium.

Adult↗

PubMed1998

Monilethrix: a keratin hHb6 mutation is co-dominant with variable expression.

Monilethrix is a rare autosomal dominant disease characterized by hair fragility and hyperkeratotic papules. Mutations in type-II hair specific keratins hHb6 and hHb1 have recently been reported. We describe a large family with a E410D mutation in the evolutionary conserved helix termination motif of keratin hHb6 that was variably expressed among 12 heterozygous members, and severely expressed among 3 homozygous members. These 3 patients had essentially complete lack of scalp hair since the age of 2 months with no improvement over time as well as follicular keratotic involvement extensively expressed over the scalp and large body areas. The variability seen in heterozygous patients, along with seasonal and pregnancy-related improvement suggest that other genetic or environmental factors may modify keratin gene expression. This represents the first report of a co-dominant keratin hHb6 mutation resulting in severe disease.

Base Sequence↗

PubMed1998

South American cutaneous leishmaniasis: report of ten cases in Israeli travelers.

BACKGROUND: Cutaneous South American leishmaniasis is caused by several species of leishmaniasis. Lack of appropriate treatment may lead to mucocutaneous leishmaniasis, mainly with L. b. braziliensis and L. b. panamensis. OBJECTIVE: To describe the clinical findings of Israeli travelers infected with cutaneous South American leishmaniasis and to draw attention to this problem. SUBJECTS: Ten patients were interviewed, examined and treated. RESULTS: Twenty-two lesions of cutaneous leishmaniasis were found, all in exposed areas. Patients were seen by an average three physicians (range 1-6) before the final diagnosis was confirmed by direct smear, after an average period of 125 days (range 88-270 days). Treatment with Pentostam was started after an average period of 134 days (range 94-275 days). All lesions healed completely, but with scarring. CONCLUSION: Travelers to endemic areas, as well as physicians, should be instructed about the potential risks and the clinical manifestations of cutaneous and mucocutaneous South American leishmaniasis. Such awareness will prevent undue delay in diagnosis and treatment.

Adult↗

PubMedDate not supplied

Monilethrix: mutational hotspot in the helix termination motif of the human hair basic keratin 6.

Monilethrix is a rare autosomal dominant disease characterized by hair fragility and follicular hyperkeratosis. Mutations in the human basic hair keratins hHb1 and hHb6 have recently been reported in this disease. Twelve families and sporadic cases were clinically diagnosed with monilethrix and were available for the study. The gene segment encoding the helix termination motif region of keratin hHb6 was PCR amplified and sequenced. Mutations were recognized in 6 families. Four families had the previously described mutations, Glu413Lys and Glu413Asp. In 2 unrelated families, a novel mutation, Glu402Lys, was identified. No clear association was found between the severity of the phenotype and the mutation carried. Furthermore, heterozygous members of the same family had variable degrees of hair and skin involvement. Homozygous patients identified in one large consanguineous family were more severely affected. Other genetic or environmental factors may also play a role in monilethrix.

Amino Acid Motifs↗