The tumors may cause bumps under the skin colored spots skeletal problems

The tumors may cause bumps under the skin colored

This preview shows page 72 - 84 out of 103 pages.

The tumors may cause bumps under the skin, colored spots, skeletal problems, pressure on spinal nerve roots , and other neurological problems.
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1-Neurofibromas, café-au-lait, Lisch nodules
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NEUROFIBROMATOSIS 1- (von Recklinghausen) Is a tumor disorder that is caused by the mutation of a gene on chromosome 17 that is responsible for control of cell division. NF-1 causes tumors along the nervous system. Common symptoms of NF-1 include scoliosis (curvature of the spine), learning disabilities, vision disorders, Lich nodules ( and epilepsy.
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Cutaneous neurofibromas and a 'café au lait spot' Back of an elderly woman with NF-1 Lisch nodules a pigmented hamartomatous nodular aggregate of dendritic melanocytes affecting the iris
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NEUROFIBROMATOSIS 2- Bilateral acoustic neuromas and multiple meningiomas Manifested by the development of symmetric, non- malignant brain tumors in the region of the cranial nerve VIII, which is the "auditory-vestibular nerve" that transmits sensory information from the inner ear to the brain . NF II is caused by mutations of the Merline gene which seems to influence the form and movement of cells Many people with this condition also experience visual problems.
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Hereditary Disease Caused by Sex-Linked Recessive Genes Caused by defective genes carried on the X chromosome Males affected more than women Males inherit one defective gene on X from mother to have disorder Females only affected if they inherit 2 defective genes (one from each parent)
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Ex. Hemophilia Caused by the inheritance of one recessive gene on the X (males) or two recessive genes on both X’s (females) Affects blood – blood does not clot Leads to severely increased risk of bleeding from common injuries Potentially fatal
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3. Chromosomal aberrations (cytogenetic disorders) alternations in the number or structure of chromosomes autosomes or sex chromosomes studied by cytogenetics cell cycle arrested in metaphase (colchicin) - staining by Giemsa method (G-bands) - photographing - karyotype 2 sets of 23 chromosomes 22 pairs of autosomes, 2 sex chromosomes (XX or XY) cytogenetic disorders are relatively frequent ! (1:160 newborns; 50% of spontaneous abortions)
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Structural abnormalities breakage followed by loss or rearrangement deletion, translocation Generally : loss of chromosomal material is more dangerous than gain abnormalities of sex chromosomes are better tolerated than autosomal abnormalities of sex chromosomes sometimes symptomatic in adult age (e.g. infertility) usually origin de novo (both parents and siblings are normal)
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Numerical abnormalities euploidy - normal 46 (2n) polyploidy (3n or 4n) - spontaneous abortion aneuploidy trisomy (2n+1) - 47 - compatible with life monosomy (2n-1) - autosomal - incompatible with life sex chromosomal- compatible with life Deletion Breakage
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COMMON CYTOGENETIC DISEASES AUTOSOMES TRISOMY-21 ( DOWN SYNDROME) 8, 9, 13 (Patau), 18 (Edwards), 22 22q.11.2 deletion SEX CHROMOSOMES KLINEFELTER : XXY, XXXY, etc.
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