RESUMO
Three fragile sites 2q13, 12q13, and 17p12 were found in one family. In the index case, who was first investigated in 1969 for low birth weight and bilateral inguinal hernia, three tissues were examined, blood, marrow, and skin. Three of the family have been reinvestigated after 17 years. Cultures for sister chromatid exchange (SCE) and the effects of aphidicolin, fluorodeoxyuridine (FUdR), bromodeoxyuridine (BrdU), and methotrexate on the frequency of the fragilities were studied. The mother of the index case who is an obligate carrier for the fragile 2q13 does not express it in folate/thymidine deficient medium. Further studies on her using a lymphoblastoid cell line, showed that there was a reduced level of fragility of 12q13 and 17p12 in B-lymphocytes compared to T-lymphocytes. Excess thymidine and FUdR when added to the lymphoblastoid cell line did not induce the 2q13. These studies also confirm the induction of a range of common fragile sites by treatment with aphidicolin, showing in addition homozygosity for at least 3p14, 6q26, 16q23, and Xp22. There were no detectable increases in the SCE rate between individuals with fragile sites and the five controls tested. There was no history of cancer or phenotypic abnormalities in the family.
Assuntos
Fragilidade Cromossômica , Cromossomos Humanos 1-3 , Cromossomos Humanos 16-18 , Cromossomos Humanos 6-12 e X , Adolescente , Afidicolina , Células Cultivadas , Bandeamento Cromossômico , Sítios Frágeis do Cromossomo , Diterpenos/farmacologia , Feminino , Ácido Fólico/farmacologia , Humanos , Cariotipagem , Masculino , Linhagem , Troca de Cromátide Irmã/efeitos dos fármacosRESUMO
A 32-year-old mentally retarded woman was found to have a complex rearrangement of one chromosome 4. Her karyotype is interpreted as 46,XX,inv(4) (pter----p14::q12----p14::q12----qter) del (4) (pter----15.33::p15.2----qter). Clinically she does not show the features of the Wolf-Hirschhorn syndrome. Her phenotype and cytogenetic findings are compared with 2 other reported cases of 4p-without Wolf-Hirschhorn syndrome.
Assuntos
Cromossomos Humanos 4-5 , Deficiência Intelectual/genética , Adulto , Bandeamento Cromossômico , Deleção Cromossômica , Inversão Cromossômica , Feminino , Humanos , Cariotipagem , Fenótipo , SíndromeRESUMO
Two cases of ring chromosome 11 are reported. Both had mental retardation, microcephaly, and short stature. High resolution G banding in case 1 showed no visible loss of chromatin, the karyotype being assessed as 46,XX,r(11) (p15 X 4q2 X 5). In case 2, a Wilm's tumour developed at 8 months and the child died at 18 months. Cytogenetic analysis by Q banding demonstrated minimal chromosome deletion and the karyotype was considered to be 46,XY,r(11) (p15q25).
Assuntos
Aberrações Cromossômicas , Cromossomos Humanos 6-12 e X , Anormalidades Múltiplas/genética , Bandeamento Cromossômico , Feminino , Transtornos do Crescimento/genética , Humanos , Lactente , Deficiência Intelectual/genética , Neoplasias Renais/genética , Masculino , Microcefalia/genética , Tumor de Wilms/genéticaRESUMO
We report a paracentric inversion of 1p in a boy with mild mental retardation. The chromosome aberration was identified by high resolution chromosome banding, and was also present in his phenotypically normal mother and other relatives. The boy's karyotype was considered to be 46,XY,inv(1) (p31,2p36.22) ISCN (1981).