Central nervous system (CNS) invasion by bacteria of the genus

Cystic fibrosis (CF) is the most common autosomal recessive disease in the Caucasian population. The disease can be caused by one of the more than 900 different mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. However, the deletion of the phe508-codon is the most prevalent mutation observed. Our aim was to perform a screening for this mutation (DeltaF508, or F508del) in the population of Mendoza, Argentina. For the screening, 1,000 blood samples were obtained from CF asymptomatic individuals and combined into 100 pools each containing 10 different blood samples. Pools containing at least one F508del carrier were detected by heteroduplex formation during the PCR amplification of exon 10. The PCR was designed to introduce a recognition site for a restriction enzyme that confirmed the presence of the deletion F508del in the positive pools. The results with this simple method indicate a frequency of carriers in the Mendoza population of 2.1% (1.3%-3.2, 95% confidence limits). The observed frequency of carriers is similar to that reported for European populations. Hum Mutat 18:167, 2001.

Background: Deletions in the SHOX gene are the most frequent genetic cause of Leri-Weill syndrome and Langer mesomelic dysplasia, which are also present in idiopathic short stature. Aim: To describe the molecular and clinical findings observed in 23 of 45 non-consanguineous Chilean patients with different phenotypes related to SHOX deficiency. Methods: Multiplex ligation-dependent probe amplification was used to detect the deletions; the SHOX coding region and deletion-flanking areas were sequenced to identify point mutations and single-nucleotide polymorphisms (SNPs). Results: The main genetic defects identified in 21 patients consisted of deletions; one of them, a large deletion of >800 kb, was found in 8 patients. Also, a smaller deletion of >350 kb was observed in 4 patients. Although we could not precisely determine the deletion breakpoint, we were able to identify a common haplotype in 7 of the 8 patients with the larger deletion based on 22 informative SNPs. Conclusion: These results suggest that the large deletion-bearing allele has a common ancestor and was either introduced by European immigrants or had originated in our Amerindian population. This study allowed us to identify one recurrent deletion in Chilean patients; also, it contributed to expanding our knowledge about the genetic background of our population.

Background: Multiple endocrine neoplasias type 2A (MEN 2A) is a dominantly inherited cancer syndrome. Missence mutations in the codon encoding cysteine 634 of the ret proto-oncogene have been found in 85% of the MEN 2A families. The main tumour type always present in MEN 2A is medullar thyroid carcinoma (MTC). Only 25% of all MTC are hereditary, and generally they are identified by a careful family history. However, some familial MTCs are not easily detected by this means and underdiagnosis of MEN 2A is suspected.