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Tiny interstitial duplication of proximal 7q in association with a maternal paracentric inversion
Human Genetics
|January 1, 1982
Insights
A paracentric inversion of chromosome 7 was identified in an infant with birth defects and her mother. Unequal crossing over during meiosis likely caused a small duplication, leading to the infant's malformations.
Area of Science:
- Genetics
- Human Genetics
- Medical Genetics
Background:
- Chromosomal abnormalities can lead to congenital malformations.
- Paracentric inversions are structural rearrangements of chromosomes.
- Genetic analysis is crucial for diagnosing developmental disorders.
Observation:
- A female infant presented with multiple congenital malformations.
- She and her phenotypically normal mother shared a paracentric inversion of chromosome 7.
- The infant's inverted chromosome 7 had an additional small dark band.
Findings:
- The paracentric inversion of chromosome 7 was identified in both mother and infant.
- An unequal crossing over event during maternal meiosis is hypothesized.
- This event is presumed to have caused a small interstitial duplication in the infant.
Implications:
- This case highlights how chromosomal rearrangements can result in complex phenotypes.
- Understanding meiotic recombination is vital for genetic counseling.
- Further research into submicroscopic duplications associated with inversions is warranted.
Abstract:
Paracentric inversion of chromosome 7 was found in a female infant with multiple malformations and in her phenotypically normal mother. Examination of prometaphase chromosomes revealed an additional small dark band on the inverted chromosome 7 of the girl. It was assumed that an unequal crossing over at the base of a meiotic loop of chromosome 7 had occurred in the mother and resulted in a tiny interstitial duplication in the girl.