RESUMO
Recent data has suggested that familial recurrent hydatidiform mole is a rare autosomal recessive trait in women experiencing this gestational disease (MIM 231090). Here we provide molecular data on an additional family confirming that recurrent familial hydatidiform moles are diploid, biparental and arise from independent conceptions. A narrowing of the gene interval on chromosome 19q13.3-13.4 is suggested by haplotype analysis in two sisters.
Assuntos
Cromossomos Humanos Par 19/genética , Mola Hidatiforme/genética , Adulto , Aberrações Cromossômicas , Transtornos Cromossômicos , Mapeamento Cromossômico , Saúde da Família , Feminino , Ligação Genética , Haplótipos , Homozigoto , Humanos , Escore Lod , Masculino , Repetições de Microssatélites , Linhagem , Ploidias , Gravidez , Sitios de Sequências Rotuladas , Neoplasias Uterinas/genéticaRESUMO
GJB2 mutation analysis was performed in 179 unrelated subjects with sporadic or familial hearing loss (HL). Among 57 families, 18 showed a vertical transmission of HL, the disease being present in two or three generations. Besides 155 nonsyndromic cases, 24 patients presenting with extra-auditory clinical signs were included in the molecular study. GJB2 mutation analysis was also performed in 19 subjects with an anamnestic history of perinatal risks factors for acquired HL. The 35delG mutation accounted for 22.1% of analyzed chromosomes in sporadic cases and 39.4% in familial cases; 35delG prevalence reached 41% in autosomal recessive and 44.4% in pseudodominant pedigrees. Two novel GJB2 mutations were identified in compound heterozygosity with 35delG allele (D159V, 284ins/dup[CACGT]). Two 35delG homozygous subjects were identified among HL cases classified as environmental in origin. Four patients 35delG heterozygous (35delG/V95M, 35delG/L90P, 35delG/167delT, and 35delG/?) and two homozygous presented with extra-auditory clinical signs involving different organs (skin, vascular system, hemopoietic lineages, and thyroid). In a high proportion of 35delG heterozygous HL patients (52%), no second GJB2 mutation was detected. The reported data highlight the complexity of the genetic epidemiology of GJB2-linked deafness, further enlarging the spectrum of situations in which GJB2 mutation analysis should be performed. The presence of extra-auditory signs in a significant portion of GJB2-mutated patients suggests the possibility that GJB2 loss of function could contribute to clinical phenotypes presenting in association with deafness. This hypothesis deserves further investigation. The failure to identify a presumed partnering GJB2 mutation in a high proportion of deaf patients remains a challenging problem to be clarified.
Assuntos
Conexinas/genética , Surdez/genética , Ligação Genética , Sequência de Aminoácidos , Audiologia , Conexina 26 , Conexinas/química , Surdez/epidemiologia , Surdez/patologia , Humanos , Dados de Sequência Molecular , Prevalência , Homologia de Sequência de AminoácidosRESUMO
A systematic search was made for uniparental disomy (UPD) in familial or de novo balanced Robertsonian translocations, identified by prenatal cytogenetic investigations. Parent-of-origin studies were performed using molecular markers for both chromosomes involved in the translocation. No UPD cases were identified out of 23 analysed cases. The results presented here, combined with other available data, provide preliminary elements for genetic counselling in these common chromosomal rearrangements.