Chromosome Abnormalities

Chromosome Abnormalities

Trisomy Conditions Humans have 23 pairs of chromosomes A trisomy is a chromosomal disorder characterised by an additional chromosome, so the person has 47 instead of 46 which leads to other physical/mental characteristics Down Syndrome, Edward Syndrome and Patau Syndrome are the most common forms of trisomy. ... Down Syndrome Extra copy of genetic material on the 21st chromosome (aka Trisomy 21) An error in cell division "nondisjunction" resulting in the father's sperm or the mother's egg cell containing an extra/abnormal number of chromosomes - Not usually genetic Monosomy Conditions Monosomy is when a diploid organism has only one copy of one of its chromosomes instead of two. Very rare in autosomes - body cells without pairs don't tend to survive - but can occur in the sex chromosome - E.g. Turner Syndrome ... Turner Syndrome Tend to be short and struggles in reproduction Characterised by one X and no second Chromosome (X or Y) on the sex chromosome Not usually genetic