Chromosomal Abnormalities Flashcards
(14 cards)
What are the two forms of Chromosomal Abnormalities?
1.Numerical Abnormalities
2. Structural Abnormalities
How many % of conceptions ends in Spontaneous Abortions due to chromosomal Abnormalities?
50% of conceptions.
How many % of conceptuses have major chromosomal defects?
About 25%
What are the most common Chromosomal Abnormalities?
- Turner Syndrome
- Trisomy 16, 17, 18, 21
- Klinefelter’s syndrome.
Non-disjunction is primarily due to…
Mis-segregation of chromosomes during Anaphase 1.
Chromosomal Abnormalities increases with?
Increase maternal age (>35y/o)
What is TRISOMY?
Additional gene on the Chromosomes.
What is MONOSOMY?
A decrease in the number of gene on the Chromosome.
What is TRISOMY 21?
Down Syndrome
An extra copy of Chromosome 21.
80% Maternal
Clinical signs of down Syndrome
Growth Retardation
Mental deficiencies
Flat face features
Epicanthal folds
Face looking as if they want to sleep.
Small ears.
Low muscle tone(hypotonia)
What is Klinefelter’s syndrome?
It is a sex-limked Trisomy that is characterized by 47 chromosomes.
Found only in men.
Genotype –XXY
Clinical features of Klinefelter’s Syndrome
Sterility
Testicular Atrophy
Gynecomastia
Broad hips
Tall and lesser IQ
Late talker.
What is Turner Syndrome?
A monosomy chromosomal Abnormality characterized with 45 chromosomes.
Occurs in Females and is cause is 80% paternal(loss of X chromosome)
Clinical Features of Turner Syndrome
No Ovaries
Short Stature
Webbed neck, lymphedema of extremities
Coactation of Aorta
Cubitus Valgus
Abnormal moles
