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Printable Handouts
Navigable Slide Index
- Introduction
- Learning points
- Chromosome disorders are common
- G banded male karyotype
- Numerical chromosome abnormalities
- Triploidy 69,XXX
- Triploidy – diandry
- Triploidy – digyny
- Aneuploidy
- Trisomy 21 karyotype
- Monosomy 4p metaphase spread
- Whole chromosome aneuploidy (1)
- Whole chromosome aneuploidy (2)
- Maternal age and chromosome abnormalities
- Nondisjunction in a normal diploid zygote can cause mosaicism
- Chromosome mosaicism found during pregnancy
- Chromosome mosaicism: post conceptual mitotic errors
- Chromosome mosaicism: trisomy rescue
- Imprinting disorders
- Structural chromosome abnormalities
- Deletions, duplications and inversions
- Chromosome translocations
- Insertional translocations
- Balanced reciprocal translocations (1)
- Balanced reciprocal translocations (2)
- Balanced reciprocal autosomal translocations (1)
- Balanced reciprocal autosomal translocations (2)
- Balanced reciprocal autosomal translocations: types of segregation
- Emanuel syndrome (1)
- Emanuel syndrome (2)
- Robertsonian translocations
- Robertsonian translocations: segregation
- Trisomy 21 caused by a Robertsonian translocation
- Down syndrome
- Down syndrome can be familial
- Chromosome (autosome) inversions
- Pericentric inversions
- Paracentric inversions
- Summary
Topics Covered
- Chromosome abnormalities that can cause developmental disorders and miscarriage
- How and when numerical chromosome anomalies arise during meiosis and mitosis
- The inheritance of balanced chromosome translocations and inversions
- How and why balanced structural chromosome rearrangements can give rise to unbalanced genomes
- The clinical implications of chromosome abnormalities and their inheritance
Talk Citation
Holden, S. (2019, October 31). Chromosome disorders: the body of chromosomes [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved October 7, 2024, from https://doi.org/10.69645/ZQYW4516.Export Citation (RIS)
Publication History
Financial Disclosures
- Dr. Simon Holden has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
Chromosome disorders: the body of chromosomes
Published on October 31, 2019
34 min
Other Talks in the Series: Introduction to Human Genetics and Genomics
Transcript
Please wait while the transcript is being prepared...
0:00
I'm Dr. Simon Holden.
I'm a consultant in clinical genetics in
the Department of Clinical Genetics at Addenbrooke's Hospital in Cambridge,
and I'm also an associate lecturer at the University of Cambridge.
This presentation is the second part of the talk on chromosome disorders.
0:20
The aims are: that students should be
familiar with the different types of chromosome disorders,
understand how they relate to other genomic disorders,
be familiar with the nomenclature used to
describe the more common chromosome rearrangements,
understand how the behavior of chromosome rearrangements at
meiosis dictates their inheritance and their recurrence risks,
and be able to describe a chromosome rearrangement
and its clinical implications to a patient.
0:49
So, this is just a revision slide showing how common
the different types of chromosome rearrangements and imbalances are.
0:59
This slide, again, is to orientate us; it shows a G banded male karyotype.
1:08
We will now look at numerical chromosome abnormalities that can take several forms.
First, let's consider polyploidy.
This is the presence of one or more additional haploid chromosome sets.
The most common form of polyploidy is triploidy.
Here, we have three sets of the normal haploid chromosome number,
which is represented as the letter n. So, this can give rise to karyotypes such as 69, XYY.
Triploidy is the most likely numerical chromosome abnormalities
to be encountered in the first trimester of pregnancy.
It occurs when a double chromosome content,
so two haploid cells or 2n,
comes from one parent.
Triploidy affects one to three percent of recognized conceptions and
most triploid pregnancies are lost as first-trimester miscarriage or very occasionally,
the second-trimester fetal death in the womb.