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  2. Down syndrome - Wikipedia

    en.wikipedia.org/wiki/Down_syndrome

    The extra chromosome content can arise through several different ways. The most common cause (about 92–95% of cases) is a complete extra copy of chromosome 21, resulting in trisomy 21. [ 91 ] [ 96 ] In 1–2.5% of cases, some of the cells in the body are normal and others have trisomy 21, known as mosaic Down syndrome.

  3. Cri du chat syndrome - Wikipedia

    en.wikipedia.org/wiki/Cri_du_chat_syndrome

    Chromosomal Deletion. Cri du chat syndrome is a rare genetic disorder due to a partial chromosome deletion on chromosome 5. [1] Its name is a French term ("cat-cry" or "call of the cat") referring to the characteristic cat-like cry of affected children (sound sample [1]). [2] It was first described by Jérôme Lejeune in 1963. [3]

  4. Klinefelter syndrome - Wikipedia

    en.wikipedia.org/wiki/Klinefelter_syndrome

    The syndrome is defined by the presence of at least one extra X chromosome in addition to a Y chromosome, yielding a total of 47 or more chromosomes rather than the usual 46. Klinefelter syndrome occurs randomly. The extra X chromosome comes from the father and mother nearly equally.

  5. PURA syndrome - Wikipedia

    en.wikipedia.org/wiki/PURA_syndrome

    PURA syndrome. Mutation in the PURA gene, located on Chromosome 5 at 5q31. PURA syndrome, also known as PURA-related neurodevelopmental disorder, is a rare novel genetic disorder which is characterized by developmental and speech delay, neo-natal hypotonia, failure to thrive, excessive sleepiness, epilepsy, and other anomalies. [1]

  6. Chromosome 5 - Wikipedia

    en.wikipedia.org/wiki/Chromosome_5

    Chromosome 5 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 5 spans about 182 million base pairs (the building blocks of DNA) and represents almost 6% of the total DNA in cells. Chromosome 5 is the 5th largest human chromosome, yet has one of the lowest gene densities.

  7. Chromosome 5q deletion syndrome - Wikipedia

    en.wikipedia.org/wiki/Chromosome_5q_deletion...

    Chromosome 5q deletion syndrome is an acquired, hematological disorder characterized by loss of part of the long arm (q arm, band 5q33.1) of human chromosome 5 in bone marrow myelocyte cells. This chromosome abnormality is most commonly associated with the myelodysplastic syndrome. It should not be confused with "partial trisomy 5q", though ...

  8. Chromosome abnormality - Wikipedia

    en.wikipedia.org/wiki/Chromosome_abnormality

    Chromosome abnormality. A chromosomal abnormality, chromosomal anomaly, chromosomal aberration, chromosomal mutation, or chromosomal disorder is a missing, extra, or irregular portion of chromosomal DNA. [1][2] These can occur in the form of numerical abnormalities, where there is an atypical number of chromosomes, or as structural ...

  9. XYY syndrome - Wikipedia

    en.wikipedia.org/wiki/XYY_syndrome

    The syndrome is diagnosed in an increasing number of children prenatally by amniocentesis and chorionic villus sampling [24] in order to obtain a chromosome karyotype, where the abnormality can be observed. It is estimated that only 15–20% of children with 47,XYY syndrome are ever diagnosed. Of these, approximately 30% are diagnosed prenatally.