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Data on structural chromosome abnormalities identified during prenatal diagnosis were used to estimate the number of such abnormalities that would be detectable in an unselected series of newborns using moderate levels of banding (400 to 500 bands). These estimates were compared with the rates detected in nonbanded surveys of newborns. Between 1976 and 1990(More)
Cytogenetic analysis of 1000 spontaneous abortions showed 463 to have an abnormal chromosome constitution. The proportion of chromosome abnormalities varied with the gestational age of the abortus and the type of tissue cultured but was not significantly different among the five racial groups represented in the study population. It was suggested that(More)
Turner's syndrome is a sporadic disorder of human females in which all or part of one X chromosome is deleted. Intelligence is usually normal but social adjustment problems are common. Here we report a study of 80 females with Turner's syndrome and a single X chromosome, in 55 of which the X was maternally derived (45,X[m]) and in 25 it was of paternal(More)
Trisomy, occurring in at least 4% of pregnancies, is the most common chromosome abnormality in humans. The majority of trisomies are associated with single additional chromosome. The presence of an additional sex chromosome is often associated with physical, behavioral, and intellectual impairment. The presence of an additional autosome is even more(More)
  • P A Jacobs
  • 1992
The comparisons of observed and predicted rates of chromosomally abnormal gametes for two major classes of abnormality and for three specific trisomies are summarized in Table 2.10. As can be seen there is not very good agreement between the two sets of data. For sperm the observed abnormality rates are, with the exception of polyploidy, all in excess of(More)
The incidence of skewed X-inactivation in normal women is controversial, with up to 10-fold differences being reported by different authors. In order to clarify this issue, we have conducted a survey of the X-inactivation patterns in 270 informative females from various age groups, using the androgen receptor gene/polymerase chain reaction assay. Results(More)
The results of a cytogenetic and segregation analysis of 110 pedigrees of the mar (X) syndrome are reported. The cytogenetic study indicated an inverse relationship between IQ and the mar(X) frequency in females but not in males. A small but significant effect of age on mar(X) frequency was observed in both males and females, but in females it was(More)
This study investigated the phenotypic manifestations of interstitial duplications of chromosome 15 that involve the Prader-Willi/Angelman syndrome critical region (PWACR). Twenty-one affected individuals from six families were evaluated in detail, using standardized and semi-standardized measures of intelligence, psychopathology, and physical anomalies.(More)