Clin Med - Genetics Flashcards
Do single gene mediated d/o’s make up the majority of clinical genetic conditions?
True or False
False
They only make up for 10% and NOT the majority
Which clinical genetic conditions have both environmental and genetic input to account for the disorders?
Polygenic or multifactorial (complex) disorders
Which type of clinical genetic conditions make up the majority?
Polygenic or multifactorial (complex) disorders
In other words, every medical condition has a genetic component
What is a HUGE component of non-disjunction?
Maternal age
What is aneuploidy?
more or fewer than 46 chromosomes
Name the conditions containing 47 chromosomes?
Trisomy 13, 18 & 21 (Down)
Which Trisomy Syndrome has these features: cleft lip, polydactyly (post axial), rocker-bottom feet, neural tube defects with a median survival age of 2.5 days?
Trisomy 13
47, XX/XY, +13
Which Trisomy Syndrome has is characterized by the following features: Clenched fist (2nd & 5th digit overlap 3rd & 4th), rocker-bottom feet, low set ears?
Trisomy 18
47, XX/XY, +18
Which Trisomy Syndrome has the following features:
Neoteny (remain infant-like), mental retardation, low set ears, epicanthal folds, single palmar crease, hypotonic, overweight later in life, congenital heart disease, risk of leukemias?
Down Syndrome
(Trisomy 21)
47, XX/XY, +21
What syndrome has a normal phenotype, thin build, disproportionately long arms/legs
female type distribution of pubic hair, testicular dysgenesis, gynecomastia, normal IQ to MR
Klinefelter Syndrome
47, XXY
What may be associated with a higher number of X chromosomes?
subnormal intelligence or mental retardation
Tall male with small testicles and not doing well in school with some mental issues. What syndrome?
Klinefelter Syndrome
What should you be sure to have on your DDX with Klinefelter Syndrome?
ambiguous genitalia
This syndrome results from non-dysjunction at 2nd meiotic division. Features include: learning problems in school, delayed emotional maturity (aggression), very tall stature and acne.
XYY Super Male
What are the characteristics of Turner Syndrome?
Lymphedema in feet short stature ovarian failure (w/ increased LH/FSH) webbed neck (2nd to lymphedema) increased carrying angle shield chest (wide spaced nipples) HTN (coarctation of aorta)
Most Turner syndrome concepti spontaneously abort, so who are the survivors?
most likely mosaics
What type of aneuploidy is Turner Syndrome?
monoploidy
45, X
Does the XXX Syndrome result in unusual physical features and medical problems?
No d/t the inactivation of all but 1 X
What are the 4 types of Mendelian inheritance patterns?
Autosomal
X-linked
Dominant
Recessive
What is single gene inheritance referred to as?
Mendelian inheritance
What is Autosomal inheritance?
gene responsible for the phenotype is located on one of the 22 pairs of autosomes (non-sex determining chromosomes)
What is X-linked inheritance?
gene that encodes for the trait is located on the X chromosome
What is Dominant inheritance?
Conditions that are manifest in heterozygotes (individuals w/ just ONE copy of the mutant allele)