SNP genetic polymorphisms of MDR-1, CYP1A2 and CYPB11 genes in four canine breeds upon toxicological evaluation

The fields of pharmacogenetics and pharmacogenomics have become increasingly promising regarding the clinical application of genetic data to aid in prevention of adverse reactions. Specific screening tests can predict which animals express modified proteins or genetic sequences responsible for adverse effects associated with a drug. Among the genetic variations that have been investigated in dogs, the multidrug resistance gene (MDR) is the best studied. However, other genes such as CYP1A2 and CYP2B11 control the protein syntheses involved in the metabolism of many drugs. In the present study, the MDR-1, CYP1A2 and CYP2B11 genes were examined to identify SNP polymorphisms associated with these genes in the following four canine breeds: Uruguayan Cimarron, Border Collie, Labrador Retriever and German Shepherd. The results revealed that several SNPs of the CYP1A2 and CYP2B11 genes are potential targets for drug sensitivity investigations.

Mutations in the vitamin D receptor gene in four patients with hereditary 1, 25-dihydroxyvitamin D-resistant rickets / Mutações no gene do receptor de vitamin D em quatro pacientes com raquitismo hereditário resistente a 1, 25-dihydroxyvitamin D

Mutations in the vitamin D receptor (VDR) are associated to the hereditary 1,25-dihydroxivitamin D-resistant rickets. The objectives of this work are: search for mutations in the VDR and analyze their functional consequences in four Brazilian children presented with rickets and alopecia. The coding region of the VDR was amplified by PCR e direct sequenced. We identified three mutations: two patients had the same mutation in exon 7 at aminoacid position 259 (p.Q259E); one patient had a mutation in exon 8 at codon 319 (p.G319V) and another one had a mutation in exon 3 leading to a truncated protein at position 73 (p.R73X). Functional studies of the mutant receptors of fibroblast primary culture, from patients' skin biopsy treated with increasing doses of 1,25(OH)2 vitamin D showed that VDR mutants were unable to be properly activated and presented a reduction in 24-hydroxylase expression level.

Mutações no receptor de vitamina D (VDR) são associadas a raquitismo hereditário resistente a 1,25-dihidroxivitamina D. Os objetivos deste trabalho foram procurar mutações no VDR e analisar suas conseqüências funcionais em quatro pacientes com raquitismo e alopécia. A região codificadora do VDR foi amplificada por PCR e seqüenciada diretamente. Identificamos três mutações: dois pacientes apresentavam a mesma mutação no éxon 7 na posição protéica 259 (p.Q259E); um paciente apresentava uma mutação no éxon 8 no códon 319 (p.G319V) e o outro apresentava uma mutação no exon 3 resultando em uma proteína truncada na posição 73 (p.R73X). O estudo funcional dos receptores mutados nos extratos de culturas de fibroblasto primárias obtidas de biópsia de pele dos pacientes, tratados com doses crescentes de 1,25(OH)2 vitamina D demonstraram que os receptores mutantes não apresentam ativação adequada apresentando expressão reduzida de 24-hidroxilase.

Molecular characterization of 21 hydroxylase deficiency congenital adrenal hyperplasia in Egyptian children: a pilot study

Defective steroid synthesis due to derangements of 21-hydroxylase gene [CYP21] constitutes the most frequent cause of congenital adrenal hyperplasia [CAH] and is one of the most frequent inborn errors of metabolism world wide. The molecular basis of CYP21 mutations is complicated. During meiosis gene conversion occurs and transfers deleterious point mutations from the inactive [CYP21P] to the corresponding sequence of the CYP21 gene causing either complete or partial inactivation of 21-hydroxylase activity. Allele specific polymerase chain reaction [ASPCR] was used for the detection of the 4 most common mutations in CYP21 gene: Intron 2 splice mutations [IVS2-13], 8bp deletion in exon 3 [del-8bp], I172N mutation in exon 4 and V281L mutation in exon 7, in 11 salt wasting SW-CAH Egyptian infants. In the examined 22 alleles, 2 alleles were carrying del-8bp, 3 were carrying IVS2-13 mutation, 4 with I172N, 4 with V281L. In the present study the percentage of undetectable mutations was 50%. The wide range of genetic mutations reported for CYP21 gene reconfirm the marked heterogeneity of the disorder among Egyptian and calls for more extensive molecular work

Cerebrotendinous xanthomatosis: report of two Brazilian brothers

Xantomatose cerebrotendínea é doença autossômica recessiva tratável causada pelo acúmulo de lipídeos por deficiência da enzima 27-esterol hidroxilase na produção de ácido cólico e deoxicólico. Descrevemos dois irmãos brasileiros com dificuldade cognitiva e diarréia crônica. Um deles apresentava catarata bilateral. Os achados neurológicos foram dificuldade progressiva para deambular, ataxia de membros e sinais piramidais. Ambos tinham xantomas de tendão aquileu bilateralmente. O exame de ressonância magnética revelou áreas de sinal hiperintenso em ambos os hemisférios cerebelares. Descrevemos os casos com diagnóstico genético comparando-os com a literatura. O estudo do gene CYP27A1 demonstrou a mutação C1183T no exon 6.