Dorothy Pettay

Learn More
The cause of non-disjunction of chromosome 21 remains largely unknown. Advanced maternal age is associated with both maternal meiosis I (MI) and meiosis II (MII) non-disjunction events. While reduced genetic recombination has been demonstrated in maternal MI errors, the basis for MII errors remains uncertain. We studied 133 trisomy 21 cases with maternal(More)
Recent studies of trisomy 21 have shown that altered levels of recombination are associated with maternal non-disjunction occurring at both meiosis I (MI) and meiosis II (MII). To comprehend better the association of recombination with nondisjunction, an understanding of the pattern of meiotic exchange, i.e. the exchange of genetic material at the(More)
Over 300 cases of trisomy 21 were analyzed to characterize the causes of maternal non-disjunction and to evaluate the basis for maternal age-dependent trisomy 21. We confirmed the observation that recombination along 21q is reduced among non-disjoined chromosomes 21 and further demonstrated that the alterations in recombination are restricted to meiosis I(More)
We conducted a large population-based survey of fragile X (FRAXA) syndrome in ethnically diverse metropolitan Atlanta. The eligible study population consisted of public school children, aged 7-10 years, in special education-needs (SEN) classes. The purpose of the study was to estimate the prevalence among whites and, for the first time, African Americans,(More)
The identification of DNA polymorphisms makes it possible to classify trisomy 21 according to the parental origin and stage (meiosis I [MI], meiosis II [MII], or postzygotic mitotic) of the chromosomal error. Studying the effect of parental age on these subgroups could shed light on parental exposures and their timing. From 1989 through 1993, 170 infants(More)
Paternal non-disjunction of chromosome 21 accounts for 5-10% of Down syndrome cases, therefore, relative to the maternally derived cases, little is known about paternally derived trisomy 21. We present the first analysis of recombination and non-disjunction for a large paternally derived population of free trisomy 21 conceptuses ( n = 67). Unlike maternal(More)
PURPOSE We examined maternal smoking and oral contraceptive use as possible risk factors in the genesis of cases of trisomy 21 of maternal origin. This is the first epidemiological study to categorize cases of trisomy 21 by parent of origin and timing of the meiotic error before assessing possible risk factors. METHODS We used chromosome 21-specific DNA(More)
Chromosome 15 (15q11-q13) abnormalities cause two distinct conditions, Angelman syndrome (AS) and Prader-Willi syndrome (PWS). We present the first case of a child with a balanced 15;15 translocation and AS in whom molecular studies were crucial in confirming a diagnosis. DNA polymorphisms demonstrated paternal uniparental disomy for chromosome 15,(More)
To assess the possible association between aberrant recombination and XY chromosome nondisjunction, we compared pseudoautosomal region recombination rates in male meiosis resulting in 47,XXY offspring with those resulting in 46,XY and 46,XX offspring. Forty-one paternally derived 47,XXYs and their parents were tested at six polymorphic loci spanning the(More)
We report the first case of maternal uniparental disomy of chromosome 14 in humans. The male proband inherited a balanced 13;14 Robertsonian translocation from his mother. Molecular studies showed that neither chromosome 14 was of paternal origin. The proband is of above average intelligence, but he has hydrocephalus, a bifid uvula, premature puberty, short(More)