What is the karyotype of Down syndrome Class 12?
The karyotype of Down syndrome is represented as 47, XX, +21 (females) and 47, XY, +21 (males) (Fig. 8.2a). The trisomic condition is usually caused by an error in the process of cell division called non disjunction, i.e., inability of chromosomes to separate at the time of cell division.
What is the chromosome number for Down syndrome?
Babies with Down syndrome have an extra copy of one of these chromosomes, chromosome 21. A medical term for having an extra copy of a chromosome is ‘trisomy. ‘ Down syndrome is also referred to as Trisomy 21.
Does XXY cause Down syndrome?
The incidence of 48,XXY,+21 in the general population is 0.4 to 0.9 per 10,000 male births. Unlike Turner syndrome, males with Klinefelter syndrome are not usually detected in the newborn period….Figure 3.
|48,XXY,+21||Klinefelter/Down Syndrome||Hustinx et al, 1961 |
What does the following mean 47 XY 21?
Down syndrome karyotype
Description. Down syndrome karyotype (formerly called trisomy 21 syndrome or mongolism), human male, 47,XY,+21. This male has a full chromosome complement plus an extra chromosome 21.
What is the karyotype of a male with Down syndrome?
ZooWeb – Karyotypes, 47, XY, +21. These karyotypes are from abnormal males. There is a full set of 23 homologous pairs of autosomes, and an X and Y, but an extra chromosome 21. These individuals are also said to have Down syndrome.
Why is chromosome 21 Down syndrome?
Down syndrome results when abnormal cell division involving chromosome 21 occurs. These cell division abnormalities result in an extra partial or full chromosome 21. This extra genetic material is responsible for the characteristic features and developmental problems of Down syndrome.
How many chromosomes would be found in the karyotype of a Down syndrome female?
Instead of the usual 46 chromosomes present in each cell, Lejeune observed 47 in the cells of individuals with Down syndrome. It was later determined that an extra partial or whole copy of chromosome 21 results in the characteristics associated with Down syndrome.
How can a karyotype be used to diagnose Down syndrome?
Sample Collection. The first step in performing a karyotype is to collect a sample.
How to name a karyotype?
A karyotype is the number, size, and shape of chromosomes in an organism. To determine the karyotype of an organism, scientists must follow these steps: Collect a cell from an individual. Induce
What is a karyotype and how is it prepared?
display is called a karyotype. Karyotypes are prepared from isolated somatic cells, which are treated with a drug to stimulate mitosis and then grown in culture for several days.
What is the phenotype of Down syndrome?
The Down syndrome behavioural phenotype: Taking a developmental approach Deborah J Fidler, David E Most and Amy D Philofsky Individuals with Down syndrome are predisposed to show a specific behavioural phenotype, or a pattern of strengths and challenges in functioning across different domains of development. It is argued that a developmental