Chromosomes and Chromosomal Abnormalitites Flashcards
what is a chromosome recognised by?
- banding pattern
- length
- position of centromere
what are some chromosome changes that cause disease?
- aneuploidy (whole extra or missing chromosome)
- translocation (rearrangement of chromosomes)
- insertions
- deletions
- duplications
- inversions
what is trisomy 21 and what does it cause?
- an extra copy of chromosome 21
- Down Syndrome
what is trisomy 18 and what does it cause?
- an extra copy of chromosome 18
- Edward Syndrome
what is trisomy 13 and what does it cause?
- an extra copy of chromosome 13
- Patau Syndrome
what is used for rapid prenatal diagnosis of trisomy?
FISH (fluorescent in situ hybridisation) for interphase chromosome counting
what is caused by 45 X?
turner syndrome
what is caused by 47 XXX?
triple x syndrome
what is caused by 47 XXY?
klinefelter syndrome
what is robertsonian translocation?
when two acrocentric chromosomes are stuck end to end
what is an acrocentric chromosome?
A chromosome in which the centromere is located quite near one end of the chromosome. Humans normally have five pairs of acrocentric chromosomes
what can unbalanced chromosomal products?
- miscarriage (large segments)
- dysmorphic delayed child (small segments)
what is the philadelphia chromosome and what does it cause?
- specific genetic abnormality of translocation in chromosome 22 of bcr-abl
- bcr-abl is a chimeric oncogene
- 95% of chronic myelogenous leukemia (CML) cells) have Ph Ch
what condition is the result of chromosomal deletion?
x-linked ichthyosis
what condition is the result of chromosomal duplication?
charcot marie tooth disease
