RESUMO
A patient carrying a de novo 7q31-35 duplication is presented. The tandem duplication was confirmed by FISH analysis. The case seems to be the first in the literature and, in spite of the large size of the duplicated region, he shows mild facial dysmorphism and a moderate mental retardation. The clinical findings of the dup7q published cases are compared in order to define a possible common phenotype.
Assuntos
Aberrações Cromossômicas , Cromossomos Humanos Par 7 , Anormalidades Craniofaciais/genética , Transtornos Psicomotores/genética , Humanos , Lactente , Cariotipagem , MasculinoRESUMO
A complex mosaicism involving the X chromosome was found in a 35-year-old female affected by secondary amenorrhea and short stature. Her karyotype was: 45,X[20]/46,X,del(X)(pter-->q26::qter)[15]/46,X,idic(X)(pter-->q26::q26-->pter)[9]. No cell contained both abnormal X chromosomes. This observation would suggest a possible mechanism underlying the formation of isodicentric chromosomes.
Assuntos
Amenorreia/genética , Cromossomos Humanos X , Mosaicismo , Aberrações dos Cromossomos Sexuais , Transtornos dos Cromossomos Sexuais/genética , Adolescente , Adulto , Amenorreia/etiologia , Feminino , HumanosRESUMO
Mutations in the unconventional myosin VI gene, Myo6, are associated with deafness and vestibular dysfunction in the Snell's waltzer (sv) mouse. The corresponding human gene, MYO6, is located on chromosome 6q13. We describe the mapping of a new deafness locus, DFNA22, on chromosome 6q13 in a family affected by a nonsyndromic dominant form of deafness (NSAD), and the subsequent identification of a missense mutation in the MYO6 gene in all members of the family with hearing loss.
Assuntos
Cromossomos Humanos Par 6 , Surdez/genética , Cadeias Pesadas de Miosina/genética , Sequência de Aminoácidos , Animais , Mapeamento Cromossômico , Modelos Animais de Doenças , Humanos , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Mutação , Cadeias Pesadas de Miosina/química , Linhagem , Conformação Proteica , Homologia de Sequência de AminoácidosRESUMO
Fanconi anemia (FA) is a genetically heterogeneous disease with at least eight genes on the basis of complementation groups (FAA to FAH). The analysis of the FAA gene in patients suggested the existence of deletions, none of which have thus far been characterized at the genomic level. A detailed restriction map of the FAA gene with the fine localization of its 43 exons is reported in this paper. We also describe the first two genomic deletions, one of 5.0 kb and another of at least 120 kb. The former was likely the result of a recombination between related Alu sequences. Since these interspersed repeats could generate deletions and insertions by mispairing, rearrangements of this gene are a possibility in those FA families in which FAA mutations have not been identified.
Assuntos
Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Anemia de Fanconi/genética , Proteínas Nucleares , Proteínas/genética , Deleção de Sequência/genética , Sequência de Bases , Éxons/genética , Proteínas de Grupos de Complementação da Anemia de Fanconi , Humanos , Íntrons/genética , Dados de Sequência Molecular , Recombinação Genética/genética , Sequências Repetitivas de Ácido Nucleico/genética , Mapeamento por Restrição , Análise de Sequência de DNARESUMO
A cystinuria disease gene (rBAT) has been recently identified, and some mutations causing the disease have been described. The frequency of these mutations has been investigated in a large sample of 51 Italian and Spanish cystinuric patients. In addition, to identify new mutated alleles, genomic DNA has been analyzed by an accurate and sensitive method able to detect nucleotide changes. Because of the lack of information available on the genomic structure of rBAT gene, the study was carried out using the sequence data so far obtained by us. More than 70% of the entire coding sequence and 8 intron-exon boundaries have been analyzed. Four new mutations and seven intragenic polymorphisms have been detected. All mutations so far identified in rBAT belong only to cystinuria type I alleles, accounting for approximately 44% of all type I cystinuric chromosomes. Mutation M467T is the most common mutated allele in the Italian and Spanish populations. After analysis of 70% of the rBAT coding region, we have detected normal sequences in cystinuria type II and type III chromosomes. The presence of rBAT mutated alleles only in type I chromosomes of homozygous (type I/I) and heterozygous (type I/III) patients provides evidence for genetic heterogeneity where rBAT would be responsible only for type I cystinuria and suggests a complementation mechanism to explain the intermediate type I/type III phenotype.
Assuntos
Cistinúria/genética , Heterogeneidade Genética , Mutação , Polimorfismo Genético , Alelos , Sequência de Bases , DNA/análise , Genótipo , Humanos , Itália , Dados de Sequência Molecular , Fenótipo , Polimorfismo Conformacional de Fita Simples , EspanhaRESUMO
A newborn infant with the full manifestations of trisomy 9 syndrome is reported. Cytogenetic analysis reveled an homogeneous aneuploidy. Molecular studies using polymorphic microsatellites of chromosome 9 showed that non disjunction occurred at maternal meiosis II.
Assuntos
Anormalidades Múltiplas/genética , Cromossomos Humanos Par 9 , Trissomia , Anormalidades Múltiplas/patologia , Bandeamento Cromossômico , Feminino , Marcadores Genéticos , Humanos , Não Disjunção GenéticaRESUMO
The androgenetic origin of hydatidiform moles, due to a monospermic or dispermic mechanism, has been reported, and a possible pathogenetic relation with blighted ova suggested. To evaluate the origin of hydatidiform moles and their genetic relationship with blighted ova we investigated a series of samples, utilizing several hypervariable DNA polymorphisms by Southern blotting or PCR. Seven complete or partial hydatidiform mole and 49 blighted ovum cases were investigated. The results confirm the androgenetic origin of complete hydatidiform moles, which were always due in our sample to a monospermic mechanism. Our data exclude a relationship between hydatidiform moles and blighted ova, as in the latter a mixed paternal and maternal DNA contribution was always shown. A high incidence of chromosomal abnormalities in blighted ova was also found.
Assuntos
Mola Hidatiforme/genética , Óvulo/patologia , Polimorfismo Genético , Southern Blotting , Aberrações Cromossômicas , Feminino , Humanos , Mola Hidatiforme/diagnóstico , Mola Hidatiforme/diagnóstico por imagem , Itália , Cariotipagem , Masculino , Reação em Cadeia da Polimerase , Gravidez , Ultrassonografia , VietnãRESUMO
A 49,XXXXX fetus was detected in amniotic fluid cell cultures from a 39-year-old mother. On ultrasonography, growth retardation and bilateral radioulnar synostosis were found. Additional clinical manifestations were mild facial anomalies and hypoplastic ovaries depleted of oocytes. Molecular analysis showed that this aneuploidy arose by successive maternal non-disjunction.
Assuntos
Aneuploidia , Diagnóstico Pré-Natal , Cromossomo X , Adulto , Líquido Amniótico/citologia , Células Cultivadas , Feminino , Humanos , Masculino , Gravidez , Segundo Trimestre da Gravidez , Síndrome , Ultrassonografia Pré-NatalRESUMO
A stable ring chromosome 21 was found in an azoospermic man with an otherwise normal phenotype. Meiotic studies in another known azoospermic male with r(21) had indicated that breakdown of spermatogenesis resulted from pairing failure of chromosome 21, followed by degenerative changes in the chromosomes, before the cells had completed the first meiotic division. While primary sterility was a constant feature in the three adult males, eight healthy females with r(21) were fertile. However, they were at risk for Down syndrome and spontaneous abortions.
