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Biomedical subjects

D S Murthy

Publications and source records attributed to D S Murthy.

15 recordsLinked to original sources

Trisomy 18 in Kuwait.

BACKGROUND: Trisomy 18 (Edwards' syndrome, T18) is the second most common trisomy in man. We describe 118 children with regular T18 who were ascertained clinically and cytogenetically in the Kuwait Medical Genetics Centre during 1980-1997. METHODS: Ascertainment of T18 cases was performed shortly after birth. Chromosomal studies were carried out in addition to other relevant investigations. To investigate the factors associated with T18, a case-control study was carried out with 131 normal healthy newborns. Studied factors included maternal and paternal age, birth order, abortion, associated malformation, and survival. Multiple logistic regression analysis was used to adjust for confounding between variables. RESULTS: There was a preponderance of females among T18 cases (female:male ratio 2.1:1). The majority of T18 cases (53%) died before the second week of life. The most common associated anomalies were: congenital heart (38.1%) and gastrointestinal (25.4%). Multiplicity of malformations was also observed. Significant seasonal variation in T18 cases was detected with a peak in spring. Of the 118 T18 cases, 59 were delivered during 1994-1997 (average overall T18 birth prevalence rate 8.95 per 10 000 live births [95% CI: 6.66-11.23]). Concerning maternal age, 30.5% of the T18 cases' mothers were > or =35 years compared to 10.7% in the control group. The difference was statistically significant, P = 0.002. Logistic regression analysis showed that maternal age >30 years was a significant risk factor for T18, after adjusting for confounding with paternal age. Paternal age and abortion were not found to be significant risk factors. CONCLUSION: Trisomy 18 birth prevalence rate is high in Kuwait with advanced maternal age as a significant risk factor.

Abnormalities, Multiple↗

Alagille syndrome with de novo del(20) (p11.2).

We report on an Arab boy with Alagille syndrome and a de novo deletion of the short arm of chromosome 20 with a 46,XY, del(20)(p11.2) chromosome constitution. Other reported cases are briefly reviewed.

Alagille Syndrome↗

Down syndrome in Kuwait.

During a 7-year-period (1980-1986) trisomy 21 was confirmed in 635 cases (257 males and 278 females). There were 611 cases of trisomy 21 (96.2%), 12 of different translocations (1.9%), 9 of mosaicism (1.4%), and 3 with nonclassical karyotypes (0.5%). The frequency of chromosome aberrations in our study is compared to that of major world-wide cytogenetic surveys comprising 17,738 Down syndrome cases. These surveys showed that regular trisomy 21 constitutes 92.9%, translocations 4.3%, mosaicism 2.2%, and nonclassical karyotypes 0.5%.

Adolescent↗

Segregation of acrocentric chromosome association in familial dicentric Robertsonian translocation t(14p;22p), aneuploidy (trisomy-21) and heteromorphism.

The frequency and types of acrocentric chromosome association were quantitatively analysed in a Down syndrome child with unusual karyotype, 46, XX, -14, -22, t dic (14p;22p), +21, 21S+. Father and 4 sibs were heterozygous carriers for t dic (14p;22p). The variant 21S+ was inherited from the mother. The occurrence of translocation and trisomy in the same individual is extremely rare. Acrocentric chromosome association was analysed in this interesting family to understand the interrelationship of acrocentric chromosome association, Robertsonian translocation and heteromorphism, as possible predisposing factors for nondisjunction. Our findings suggest that acrocentric chromosome association is a heritable and nonrandom phenomenon. Heterozygous carriers for translocations and variants are likely to be at increased risk of nondisjunction. Long term family studies will enable to ascertain the causal-relationship of these factors more precisely.

Chromosomes, Human, Pair 14↗

Nucleolar organizer region heteromorphism associated with trisomy-21: a risk factor for non-disjunction?

An unusual nucleolar organizer region (double NOR) on chromosome 13 was observed in a Down syndrome child [47, XY, +21, dNOR(13)]. The variant chromosome was inherited from the mother [46, XX, dNOR(13)]. The extra chromosome 21 in the proband was maternal origin. The frequency of NOR chromosome association showed relatively high frequency in the mother and proband as compared to the controls. The result suggest that chromosome variants involving extra copies of NOR may indeed be involved in the meiotic nondisjunction of chromosome-21.

Child, Preschool↗

Trisomy 18q: 46,XX,13q+,t(13;18)(q32;q11) in a newborn associated with multiple congenital anomalies due to paternal reciprocal translocation, 46,XY,-13,+der(13),t(13;18)(q32;q11).

A 20-day-old female neonate presented with multiple congenital anomalies, convulsions and failure to thrive. Karyotype analysis of the proposita revealed an unbalanced translocation, 46,XX,13q+,t(13;18)(q32;q11)pat resulting in partial trisomy 18q. Her father and a 5-year-old sister were phenotypically normal, balanced translocation carriers, 46,XY,-13,+der(13),t(13;18)(q32;q11) and 46,XX,-13,+der(13),t(13;18)(q32;q11), respectively. The case presented here is the second liveborn reported with trisomy 18q and is of interest from the point of view of the structural chromosomal aberration resulting in the manifestations of most features of trisomy 18 and some of 13q monosomy. The infant died due to convulsions at the age of 2 months.

Abnormalities, Multiple↗

Cytogenetic studies in a population suspected to have chromosomal abnormalities.

The present study describes the cytogenetic findings in cases suspected with chromosomal abnormalities, in cases of mental retardation, multiple congenital malformations, clinical features of Down's syndrome, Klinefelter's syndrome, Turner's syndrome, ambiguous sex, sterility, amenorrhea and history of repeated spontaneous abortions in couples. Cytogenetic studies were done in 144 of the total 205 cases. In all, 57 (39.58%) were shown to have chromosomal abnormality and of these, 34 cases (25.7%) were Down's syndrome. Sex chromosome abnormality was found in 19 cases (13.2%). The results confirm the significant contribution of chromosomal abnormalities in the genesis of mental retardation, and abnormal sexual development.

Chromosome Aberrations↗