RESUMO
: Glanzmann thrombasthenia is an inherited severe bleeding disease. Mutations associated with Glanzmann thrombasthenia are highly heterogeneous and occur across the two genes coding for the platelet αIIbß3 integrin. This study was aimed at identifying Glanzmann thrombasthenia-associated novel mutations in Tunisian patients. Seven unrelated Glanzmann thrombasthenia patients issued from high consanguineous families (86%; 6/7 of the patients) were studied. Glanzmann thrombasthenia diagnoses were based on patients' bleeding histories and platelet aggregation tests. Screening of ITGA2B and ITGB3 genes was performed by denaturing high-performance liquid chromatography (DHPLC) analysis. Amplicons with abnormal elution profiles were subjected to direct sequencing. DHPLC/sequencing analysis identified a pathogenic homozygous mutation in exon 26 at position c.2702C>A, inducing a substitution of a serine to a stop codon (p.S901*) in the ITGA2B gene, in three patients. This mutation was only previously reported in a Glanzmann thrombasthenia patient of a Tunisian origin and not in other populations. We diagnosed a pathogenic Glanzmann thrombasthenia mutation in ITGA2B screened by DHPLC that appears to be specific to individuals of Tunisian heritage and that deserves to be investigated in first intention. As a result, we determined that performing prenatal diagnosis and setting a prevention strategy via counselling for affected heterozygote individuals will be helpful for Tunisian Glanzmann thrombasthenia families where there is still a high rate of consanguinity.
Assuntos
Códon sem Sentido , Integrina alfa2/genética , Trombastenia/diagnóstico , Trombastenia/genética , Adulto , Criança , Cromatografia Líquida de Alta Pressão , Consanguinidade , Feminino , Humanos , Integrina beta3/genética , Masculino , Técnicas de Diagnóstico Molecular , Testes de Função Plaquetária , Análise de Sequência de DNA , TunísiaRESUMO
CHAND syndrome is an autosomal recessive disorder characterized by curly hair, ankyloblepharon, and nail dysplasia. Only few patients were reported to date. A homozygous RIPK4 mutation was recently identified by homozygosity mapping and whole exome sequencing in three patients from an expanded consanguineous kindred with a clinical diagnosis of CHAND syndrome. RIPK4 was previously known to be implicated in Bartsocas-Papas syndrome, the autosomal recessive form of popliteal pterygium syndrome. We report here two cases of RIPK4 homozygous mutations in a fetus with severe Bartsocas-Papas syndrome and a patient with CHAND syndrome. The patient with CHAND syndrome harbored the same mutation as the one identified in the family previously reported. We thus confirm the implication of RIPK4 gene in CHAND syndrome in addition to Bartsocas-Papas syndrome and discuss genotype/phenotype correlations.
Assuntos
Fenda Labial/genética , Fissura Palatina/genética , Anormalidades do Olho/genética , Doenças Palpebrais/genética , Doenças do Cabelo/genética , Joelho/anormalidades , Transtornos do Desenvolvimento da Linguagem/genética , Unhas Malformadas/genética , Proteínas Serina-Treonina Quinases/genética , Sindactilia/genética , Pré-Escolar , Fenda Labial/diagnóstico , Fenda Labial/fisiopatologia , Fissura Palatina/diagnóstico , Fissura Palatina/fisiopatologia , Consanguinidade , Exoma/genética , Anormalidades do Olho/diagnóstico , Anormalidades do Olho/fisiopatologia , Doenças Palpebrais/diagnóstico , Doenças Palpebrais/fisiopatologia , Feminino , Feto , Doenças do Cabelo/diagnóstico , Doenças do Cabelo/fisiopatologia , Homozigoto , Humanos , Recém-Nascido , Joelho/fisiopatologia , Transtornos do Desenvolvimento da Linguagem/diagnóstico , Transtornos do Desenvolvimento da Linguagem/fisiopatologia , Masculino , Mutação , Unhas Malformadas/diagnóstico , Unhas Malformadas/fisiopatologia , Sindactilia/diagnóstico , Sindactilia/fisiopatologiaRESUMO
Polymorphisms in the CD40 ligand gene (CD40LG) are associated with various immunological disorders such as tumors, autoimmune and infectious diseases. The aim of this study was to develop a highly optimized double quadruplex tetra-primer amplification refractory mutation system PCR (double quadruplex T-ARMS-PCR) coupled with capillary electrophoresis to allow genotyping of eight relevant candidate CD40LG SNPs and to establish haplotypes. After conducting the double quadruplex T-ARMS-PCR, the genotypes obtained through agarose electrophoresis were compared with those obtained through capillary electrophoresis. This strategy was applied to analyze the genetic patterns of CD40LG in two distinct cohorts of blood donors (211 French and 274 Tunisian). The T-ARMS-PCR method was rapid, inexpensive, reproducible and reliable for SNP determination. Regarding the separation technique, capillary electrophoresis allows traceable and semi-automated analysis while agarose electrophoresis remains a cost-effective technique that does not require specialized or costly equipment. Using these methods, we identified significantly different genetic heterogeneity between the two investigated populations (p ≤ 0.0001) and we also extensively characterized their haplotypes. The obtained genotype distribution and the optimized quadruplex T-ARMS-PCR technique coupled with capillary electrophoresis provides valuable information for studying pathologic inflammation leading to various diseases in which CD40LG might be a candidate gene.
