RESUMO
OBJECTIVE: Endometrial cancer is the second most frequent neoplasm in women with Lynch syndrome (LS). We sought to assess whether analyzing women with endometrial cancer would identify families with LS not identified with current clinical criteria. METHODS: We included women diagnosed with endometrial cancer younger than 50 years and also older if they had a family cancer history associated with LS. In blood samples obtained, we analyzed mutations in mismatch repair (MMR) genes, as well as protein expression by immunohistochemistry and microsatellite instability (MSI) in tumour tissue. RESULTS: A total of 103 patients were enrolled. We detected 14 pathogenic mutations and 4 genetic variants of unknown clinical significance in MMR genes. We found MSI in 41.66% of the women with a pathogenic mutation. In this group, 76.92% showed loss of at least one MMR protein. Women with mutations were younger at diagnosis, but all of them had a family history compatible with LS. CONCLUSIONS: Analysis of the MMR genes, in particular MSH6, seems to be appropriate in women with endometrial cancer and a family history of tumours associated with LS.
Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Reparo de Erro de Pareamento de DNA/genética , Neoplasias do Endométrio/genética , Instabilidade de Microssatélites , Adulto , Fatores Etários , Proteínas de Ligação a DNA/análise , Proteínas de Ligação a DNA/genética , Neoplasias do Endométrio/química , Feminino , Humanos , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL/análise , Proteína 1 Homóloga a MutL/genética , Proteína 2 Homóloga a MutS/análise , Proteína 2 Homóloga a MutS/genética , Mutação , Estudos Prospectivos , Estudos RetrospectivosRESUMO
The MECP2 gene located on Xq28 is one of the most important genes contributing to the spectrum of neurodevelopmental disorders. Therefore, we present our experience in the molecular study of this gene. MECP2 was thoroughly tested for the presence of mutations (sequencing of four exons and rearrangements) in 120 female patients: 28 with classic Rett syndrome, five with atypical Rett syndrome, and 87 with heterogeneous phenotypes with some Rett-like features. Another 120 female patients with intellectual disability of unknown origin were also studied, but in these cases we only tested exons 3 and 4. Finally, 861 healthy controls (519 females and 342 males) were also studied for exon 3 and 4. Eighteen different pathological mutations were found, five of them previously undescribed, and four large deletions detected by multiplex ligation-dependent probe amplification. All were de novo mutations not present in the parents. In conclusion, i) MECP2 is one of the most important genes in the diagnosis of genetic intellectual disability in females; ii) MECP2 must be studied not only in patients with classical/atypical Rett syndrome but also in patients with other phenotypes related to Rett syndrome; and iii) for the new variants, it is important to perform complementary studies, including the analysis of large populations of healthy individuals and the use of in silico programs.
Assuntos
Proteína 2 de Ligação a Metil-CpG/genética , Estudos de Casos e Controles , Biologia Computacional , Éxons , Feminino , Transtornos Heredodegenerativos do Sistema Nervoso/diagnóstico , Transtornos Heredodegenerativos do Sistema Nervoso/genética , Humanos , Masculino , Mutação , Fenótipo , Polimorfismo Genético , Síndrome de Rett/diagnóstico , Síndrome de Rett/genéticaRESUMO
BACKGROUND: Mutations in the cyclin-dependent kinase-like 5 gene (CDKL5) located in the Xp22 region have been shown to cause a subset of atypical Rett syndrome with infantile spasms or early seizures starting in the first postnatal months. METHODS: We performed mutation screening of CDKL5 in 60 female patients who had been identified as negative for the methyl CpG-binding protein 2 gene (MECP2) mutations, but who had current or past epilepsy, regardless of the age of onset, type, and severity. All the exons in the CDKL5 gene and their neighbouring sequences were examined, and CDKL5 rearrangements were studied by multiplex ligation-dependent probe amplification (MLPA). RESULTS: Six previously unidentified DNA changes were detected, two of which were disease-causing mutations in the catalytic domain: a frameshift mutation (c.509_510insGT; p.Glu170GlyfsX36) and a complete deletion of exon 10. Both were found in patients with seizures that started in the first month of life. CONCLUSIONS: This study demonstrated the importance of CDKL5 mutations as etiological factors in neurodevelopmental disorders, and indicated that a thorough analysis of the CDKL5 gene sequence and its rearrangements should be considered in females with Rett syndrome-like phenotypes, severe encephalopathy and epilepsy with onset before 5 months of age. This study also confirmed the usefulness of MLPA as a diagnostic screening method for use in clinical practice.
