Tue Nov 26 2002 13:30:00 GMT-0500 (Eastern Standard Time) · The typical human karyotypes contain 22 pairs of autosomal chromosomes and one pair of sex chromosomes (allosomes). The most common karyotypes for females contain two X chromosomes and are denoted 46 XX; males usually have both an X and a Y chromosome denoted 46 XY. Approximately 1.7% percent of humans are intersex sometimes due to variations in sex chromosomes .
Turner syndrome (TS) also known 45 X or 45 X0 is a genetic condition in which a female is partly or completely missing an X chromosome . Signs and symptoms vary among those affected. Often a short and webbed neck low-set ears low hairline at the back of the neck short stature and swollen hands and feet are seen at birth. Typically they develop menstrual periods and breasts only with …
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Aneuploidy is the presence of an abnormal number of chromosomes in a cell for example a human cell having 45 or 47 chromosomes instead of the usual 46. It does not include a difference of one or more complete sets of chromosomes .A cell with any number of complete chromosome sets is called a euploid cell.. An extra or missing chromosome is a common cause of some genetic disorders.
Karyotypes describe the number of chromosomes and what they look like under a light microscope. Attention is paid to their length the position of the centromeres banding pattern any differences between the sex chromosomes and any other physical characteristics. Karyotyping uses a system of studying chromosomes to identify genetic abnormalities and evolutionary changes in the past.
Complete loss of an entire X chromosome accounts for about half the cases of Turner syndrome.The importance of both X chromosomes during embryonic development is underscored by the observation that the overwhelming majority (>99%) of fetuses with only…