Chromosomal Genetic Variants Flashcards
Trisomy 13 is also known as…
Patau syndrome
Trisomy 18 is also known as…
Edward’s syndrome
In Klinefelter syndrome, there is…
An extra X chromosome (XXY)
What is the only aneuploidy with a full missing chromosome that is compatible with life?
Turner’s syndrome (monosomy X)
What is a balanced translocation and what might some signs be?
- No net gain or loss of chromosomal material
- May see infertility or multiple miscarriages
What is an inversion?
Reversal of chromosomal material from one segment to the other - usually harmless but can create imbalance gametes
Cri Du Chat Syndrome is represented by…
A deletion in chromosome 5
Are all chromosomal deletions and duplications visible by routine karyotype?
No - may need a microarray or FISH to see micro-deletions/duplications
Common reasons for genetic referrals include…
Multiple congenital anomalies, growth abnormalities, neurological diseases, arrhythmias, cardiomyopathy, seizures, autism, developmental delay, looking different (dysmorphic features), family history of genetic disease, etc.
The most common cytogenetic test to diagnose aneuploidy is…
Karyotype or FISH (FISH is faster)
What is a Robertsonian translocation?
Occurs when the two long (q) arms of two separate acrocentric chromosomes fuse to create one chromosome. The short (p) arms are usually lost, or fuse to form one small, short chromosome.
What is the first line test for suspected genetic disease in children with developmental disability?
Microarray
Karyotypes can detect…
Large chromosomal deletions or duplications, balanced and unbalanced translocations, inversions, and aneuploidy
What is the difference between FISH and microarray in terms of utility?
FISH - can look for SPECIFIC microdeletions and microduplications; good for microarray follow-up studies
Microarray - can detect ALL microdeletions, microduplications, as well as large chromosomal deletions/duplications, aneuploidy, and unbalanced translocations
