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Trisomy 21. Down syndrome (also known by the karyotype 47,XX,+21 for females and 47,XY,+21 for males) [98] is mostly caused by a failure of the 21st chromosome to separate during egg or sperm development, known as nondisjunction. [91] As a result, a sperm or egg cell is produced with an extra copy of chromosome 21; this cell thus has 24 ...
Genetics of Down syndrome. Down syndrome is a chromosomal abnormality characterized by the presence of an extra copy of genetic material on chromosome 21, either in whole (trisomy 21) or part (such as due to translocations). The effects of the extra copy varies greatly from individual to individual, depending on the extent of the extra copy ...
Dup - Duplication of a gene or genes. C – Whole chromosome extra, missing, or both (see chromosome abnormality) T – Trinucleotide repeat disorders: gene is extended in length. A cherry red spot, which can be a feature of several storage disorders, including Tay–Sachs disease. Disorder. Chromosome. Mutation.
Down syndrome is a genetic disorder that often results in distinct physical differences and intellectual disability. According to the Centers for Disease Control, each year about 6,000 babies are ...
A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosome abnormality. Although polygenic disorders are the most common, the term is mostly used when discussing disorders with a single genetic cause ...
In honor of Down Syndrome Awareness Month, which happens every October, we rounded up some informative facts about the chromosomal condition.
[citation needed] An example of trisomy in humans is Down syndrome, which is a developmental disorder caused by an extra copy of chromosome 21; the disorder is therefore also called trisomy 21. [7] An example of monosomy in humans is Turner syndrome, where the individual is born with only one sex chromosome, an X. [8]
In humans, inheritance of X-linked recessive traits follows a unique pattern made up of three points. The first is that affected fathers cannot pass X-linked recessive traits to their sons because fathers give Y chromosomes to their sons. This means that males affected by an X-linked recessive disorder inherited the responsible X chromosome ...