Chromosomal Disorders

1. By; omer Aslankan
Chromosomal Disorders
Normal Karyotype
human somatic cells contain 46 chromosomes;
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these comprise 22 homologous pairs of autosomes and two sex chromosomes, XX in the female and XY in the
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male.
normal male (46,XY)
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normal Female (46,XX)
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Structural Abnormalities of Chromosomes
abnormal number of chromosomes
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Insertion
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Deletion
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Robertsonian translocation
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Mosaic
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autosomal chromosome disorders
1) Trisomy 13;
Pataus syndrome; is a person has an extra chromosome.
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Karyotaype; (47,XX,+13 or 47,XY,+13);
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Caused; ıt is having 3 copies of chromosome 13 in each cell, instead of 2
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symptoms; Severe mental retardation, cleft lip/palate, heart defects
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2) Trisomy 18;
Edwards syndrome; is a person has an extra chromosome.
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Karyotaype; (47,XX,+18 or 47,XY,+18)
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Caused; it is having 3 copies of chromosome 18 in each cell in the body, instead of 2
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symptoms; is Severe mental retardation, rocker-bottom feet, Small mouth & chin
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3) Trisomy 21;
Down syndrome is a person has an extra chromosome.
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Down syndrome is meiotic nondisjunction.
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Karyotaype; (47,XX,+21 or 47,XY,+21)
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symptoms; mental retardation, eye abnormalities, A short neck, Small ears, Small hands and feet.
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Caused; ıt is having 3 copies of chromosome 21 in each cell, instead of 2
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Clinical features; Flat facial profile, oblique Palpebral fissures, epicanthic folds
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4) DiGeorge (22q11.2 Deletion or Velocardiofacial) Syndrome;
is caused by a deletion of a small part of chromosome 22
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Causes; small eyes, small ears, mean IQ in low 70s, overt cleft palate,hyperthyroidism, heart disease
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sex chromosome disorders
1) Klinefelter Syndrome;
Klinefelter syndrome; is a sex chromosomal disorders
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Caused; it is have extra copy of the X chromosome (affects males only)
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Karyotaype; 47, XXY
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symptoms; small testicles, tall height, tall arms and legs
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2. 2) Turner Syndrome
Turner Syndrome; is a sex chromosomal disorders
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Caused; having only one X chromosome (affects females only)
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Karyotaype; 45, X
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symptoms; short height, heart defects, failure of ovaries to develop.
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