This document discusses genomic disorders caused by DNA rearrangements such as deletions, duplications, inversions, and insertions ranging from kilobases to megabases. These rearrangements are mediated by mechanisms involving non-allelic homologous recombination between low-copy repeats, also called segmental duplications. Several genomic disorders are described that result from rearrangements between specific low-copy repeats, including deletions causing Wolf-Hirschhorn syndrome, Williams-Beuren syndrome, and Prader-Willi syndrome. Diagnostic methods for detecting DNA rearrangements are also summarized, such as fluorescence in situ hybridization, pulsed-field gel electrophoresis, array comparative genomic hybridization, and multiplex ligation-
This document discusses several types of genetic disorders including chromosomal abnormalities, changes in chromosome number or structure, uniparental disomy, chromosomal mosaicism, and mitochondrial disorders. It provides examples of specific genetic syndromes such as Down syndrome, Patau's syndrome, Edward's syndrome, Turner's syndrome, and Klinefelter's syndrome that are caused by abnormalities involving chromosome number. The document notes that genetic disorders can be caused by heredity, new mutations, or changes during formation of egg or sperm cells and can involve imbalance of genetic information.
This document discusses trisomy, which is a type of aneuploidy where there are three instances of a particular chromosome instead of the normal two. It describes how trisomy occurs due to errors in meiosis where chromosomes fail to separate properly. The most common types of trisomy in humans are trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome). Trisomy can cause birth defects, intellectual disabilities, and shortened life expectancy depending on which chromosome is involved. Rare cases of other trisomies like 8, 9, 14, 16, and 22 are also discussed.
This document discusses genomic disorders caused by DNA rearrangements such as deletions, duplications, inversions, and insertions ranging from kilobases to megabases. These rearrangements are mediated by mechanisms involving non-allelic homologous recombination between low-copy repeats, also called segmental duplications. Several genomic disorders are described that result from rearrangements between specific low-copy repeats, including deletions causing Wolf-Hirschhorn syndrome, Williams-Beuren syndrome, and Prader-Willi syndrome. Diagnostic methods for detecting DNA rearrangements are also summarized, such as fluorescence in situ hybridization, pulsed-field gel electrophoresis, array comparative genomic hybridization, and multiplex ligation-
This document discusses several types of genetic disorders including chromosomal abnormalities, changes in chromosome number or structure, uniparental disomy, chromosomal mosaicism, and mitochondrial disorders. It provides examples of specific genetic syndromes such as Down syndrome, Patau's syndrome, Edward's syndrome, Turner's syndrome, and Klinefelter's syndrome that are caused by abnormalities involving chromosome number. The document notes that genetic disorders can be caused by heredity, new mutations, or changes during formation of egg or sperm cells and can involve imbalance of genetic information.
This document discusses trisomy, which is a type of aneuploidy where there are three instances of a particular chromosome instead of the normal two. It describes how trisomy occurs due to errors in meiosis where chromosomes fail to separate properly. The most common types of trisomy in humans are trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome). Trisomy can cause birth defects, intellectual disabilities, and shortened life expectancy depending on which chromosome is involved. Rare cases of other trisomies like 8, 9, 14, 16, and 22 are also discussed.
2. • Líkamar okkar eru settir saman úr milljörðum
frumna. Í flestum frumum eru 46 litningar .
Litningarnir eru gerðir úr ákveðnu efni sem
kallast DNA
3. • Við erfum eitt sett af 23 litningum frá móður
okkar og eitt sett frá föður okkar.
• Við erfum tvö eintök flestra gena frá
foreldrum okkar, annað eintakið frá föður og
hitt frá móður.
• Þess vegna erum við lík báðum foreldrum
okkar.
4. • Þó vitað sé að erfðagallar valdi Down heilkenni er
ekki vitað hvað veldur erfðagallanum.
• Líkur á Down heilkenni aukast eftir því sem móðirin
er eldri.
• Ef móður er 35 ára eru líkurnar ein af hverjum 350
fæðingum en ef móðirin er undir 25 ára aldri þá eru
líkur á barni með Down heilkenni einungis í einni af
hverjum 1400 fæðingum.
