RESUMEN
Cytogenetic data obtained from investigating 1001 patients of Down syndrome (DS) and their parents over a period of 20 years (January 1979-January 1999) are presented. The frequency of pure trisomy, mosaicism and translocation was 87.92, 7.69 and 4.39 per cent respectively. The origin of the extra chromosome 21 due to meiotic non-disjunction was 79.24 per cent maternal and 20.76 per cent paternal. A high frequency of acrocentric chromosome associations was also observed in mothers of children of Down syndrome, this might have predisposed to an enhanced risk for non-disjunction. Birth order of DS showed a higher number of first and second borns. Reproductive performances of the parents indicated a high rate of abortions, compared to controls. Cytogenetic investigations carried out over these years greatly helped in the management of these children and for counseling the affected families.
Asunto(s)
Adolescente , Adulto , Niño , Preescolar , Aberraciones Cromosómicas , Síndrome de Down/genética , Humanos , Lactante , Recién Nacido , Mosaicismo , Translocación Genética , TrisomíaRESUMEN
Eight females with a family history of Duchenne muscular dystrophy (DMD) were analysed for their carrier status by m-calpain test, which monitors the m-calpain (milli-calpain), a proteolytic enzyme in the platelets, using an ELISA technique. Four of the eight females were identified as carriers by virtue of their elevated enzyme levels as compared to control. DNA samples of these members were analysed to ascertain the carrier status, by PCR followed by dosage analysis by densitometry. DNA analysis confirmed the findings by calpain test, which underlines the reliability of this phenotypic test for carrier detection in DMD. Calpain test has been informative in a large group of patients and carriers tested so far. Since the calpain test is cost and labour effective, it is suited for routine and widespread screening purposes.
Asunto(s)
Plaquetas/fisiología , Calpaína/genética , Ensayo de Inmunoadsorción Enzimática , Femenino , Heterocigoto , Humanos , Distrofias Musculares/genética , Linaje , Reacción en Cadena de la Polimerasa , Eliminación de SecuenciaRESUMEN
Reproductive history of mothers of 115 Down's syndrome children was studied and compared with 200 control mothers who gave birth to normal children. The frequency of spontaneous abortions in mothers of Down's syndrome babies was found to be elevated significantly (p < 0.05). The data suggest that the maternal health and reproductive potential have a prominent aetiological significance in the occurrence of Down's syndrome.
Asunto(s)
Aborto Espontáneo/etiología , Estudios de Casos y Controles , Síndrome de Down/etiología , Femenino , Humanos , Cariotipificación , Mosaicismo , Embarazo , Historia Reproductiva , TrisomíaRESUMEN
Calcium and calcium dependent enzymes viz., calcium ATPase, protein kinase C and calcium activated neutral protease (milli CANP mCANP) were studied in the erythrocytes, platelets and lymphocytes of obligate carriers, in order to assess the usefulness of these indices for detection of carriers for Duchenne muscular dystrophy (DMD). With the exception of mCANP and lymphocyte calcium ATPase, other calcium dependent enzyme activities showed considerable overlap between carriers and control. Since the increase in the level of platelet mCANP was found in all affected boys (no false negatives) and obligate carriers, and patients with other myopathic conditions and some neurogenic causes did not show high platelet mCANP activity, this parameter could be considered as a good phenotypic index. Unlike SCK, the platelet mCANP of carriers did not overlap that of controls, hence tests are to be carried out to verify its usefulness as an index of carrier state in mutations other than DNA deletion since testing of non-deletion is both costly and has practical limitations.