Trisomy of human chromosome 18: molecular studies on parental origin and cell stage of nondisjunction.
We investigated the parent and cell division of origin of the extra chromosome 18 in 62 aneuploids with a free trisomy 18 by using chromosome-18-specific pericentromeric short-sequence repeats. In 46 cases, DNA of patients was recovered from archival specimens, such as paraffin-embedded tissues and fixed chromosomal spreads. In 56 families, the supernumerary chromosome was maternal in origin; in six families, it was paternal. Among the 56 maternally derived aneuploids, we could exclude a postzygotic mitotic error in 52 cases. Among those in which the nondisjunction was attributable to an error at meiosis, 11 were the result of a meiosis I nondisjunction and 17 were caused by a meiosis II error. This result differs markedly from findings in acrocentric chromosomes where nondisjunction at maternal meiosis I predominates. Among the six paternally derived cases, two originated from a meiotic error, indicating that a nondisjunction in paternal meiosis is not as rare as previously suggested.
Eggermann
T
T
Institut für Humangenetik, Universität Bonn, Germany.
Nöthen
M M
MM
Eiben
B
B
Hofmann
D
D
Hinkel
K
K
Fimmers
R
R
Schwanitz
G
G
D000328:Adult; D001483:Base Sequence; D002887:Chromosomes, Human, Pair 18; D005260:Female; D005333:Fetus; D005819:Genetic Markers; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008423:Maternal Age; D008540:Meiosis; D008969:Molecular Sequence Data; D009630:Nondisjunction, Genetic; D010331:Paternal Age; D016133:Polymerase Chain Reaction / Q000379:methods; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics; D012189:Retrospective Studies; D013577:Syndrome; D014314:Trisomy
D005819:Genetic Markers