RESUMO
The authors report two cases of infantile metachromatic leucodystrophy in monozygotic female twins, born from a second cousin marriage (f = 1/32). The zygosity was determined by means of obstetrics and genetics marker findings.
Assuntos
Doenças em Gêmeos , Leucodistrofia Metacromática/genética , Pré-Escolar , Feminino , Marcadores Genéticos , Genótipo , Humanos , Gêmeos MonozigóticosRESUMO
We report another case of acheiropodia, a rare autosomal recessive trait of distal limb deficiency, to date seen only in Brazil in persons of Portuguese ancestry. The patient's parent were first cousins; she had two younger affected sisters. She presented with signs of vascular insufficiency of the lower stumps, which after amputation were found to lack large vessels below the knee.
Assuntos
Anormalidades Múltiplas/genética , Deformidades Congênitas do Pé , Genes Recessivos , Deformidades Congênitas da Mão , Adulto , Brasil , Consanguinidade , Feminino , Humanos , Perna (Membro)/irrigação sanguínea , Linhagem , Fenótipo , Portugal/etnologiaRESUMO
18 albinos were born on Lençóis island. Since 3 of them died and 5 emigrated, the prevalence of albinism is about 3% in the island. 2 inbred brothers with brachydactyly of the index fingers and 1 case of 'achondroplasia' were also found. The analysis of the population structure of the island suggests that its high frequency of albinism may have been produced by random drift. The index of isolation of its present population is roughly 17--27. Genealogical, clinical and histological data are presented and anslyzed. Natural selection is not acting against the albinism gene at a measurable rate. Cytogenetic investigations among albinos and normals did not reveal any difference as regards frequency of aneuploidy, association of acrocentrics and chromatid gaps. The role of random processes in evolution is mentioned and the possibility that they may be more important than it is sometimes assumed is stressed.