Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
72 Cards in this Set
- Front
- Back
|
What does metacentric mean?
|
centromere in the middle
|
|
|
What does submetacentric mean?
|
centromere off center
|
|
|
What does acrocentric mean?
|
centromere near end of chromosome
|
|
|
What is aneuploid?
|
chromosome complement that is not a multiple of 23
|
|
|
What is anaphase lag?
|
1 chromosome or chromatid lags behind, and is left out of cell or gamete.
makes monosomy of one cell, with normal chromosome # in other cell |
|
|
What is the most common cause of Downs syndrome?
|
Trisomy 21 due to nondisjunction in 95% of cases
|
|
|
What is the translocation that can produce down syndrome?
|
9p trisomy t11:22
|
|
|
What kind of translocation does the mother have usually in Down Syndrome? (for the rare type)
|
45, XX del (14;21) (q10;q10)
Typically parent has a robertsonaian translocation involving chromosome 21 with 14 or 22 |
|
|
What are the features of down syndrome?
|
flat facial profile at birth
oblique palpebral fissues brachycephaly (short AP length of head) Mental retardation epicanthic fold simian crease keratoconus, and brushfields spots |
|
|
What are the cardiac effects of down syndrome?
|
congenital heart disease
ASD VSD |
|
|
What conditions are kids with Down syndrome predisposed for later in life?
|
leukemia
alzheimers disease @ 40 |
|
|
What does the quadrule screen for Down syndrome look for?
|
decreases AFP
decreased E3 (estriol) Increased Beta hCG increased inhibin A decreased PAPP-A |
|
|
What is the genetic problem in Edwards syndrome?
|
trisomy 18
|
|
|
What are the features of Edward syndrome (trisomy 18)
|
micrognathia
low set ears overlapping fingers CHD Horseshoe kidney MR Dies w/in 1 year |
|
|
What is the genetic problem with Patau syndrome?
|
trisomy 13
|
|
|
What are the features of Patau syndrome?
|
Cleft lip and Cleft palate
microcephalus Polydactyly CHD renal defects |
|
|
What 22q11.2 deletion syndrome?
|
DiGeorge syndrome
|
|
|
What are the effects of Digeorge synrome 22q11.2
|
CATCH 22
CHD Absent thymus absent parathyroids Facial problems low calcium cleft lip |
|
|
What gene is deleted in Digeroge?
|
TBX1 gene
this is in the 22q11.2 region causes problems with 3rd/4th pharyngeal pouch development |
|
|
What are the genetic of Cri du Chat syndrome?
|
5p- deletion of short arm of 5
|
|
|
What are the characteristics of Cri du Chat syndrome? 5p-
|
cry of the cat
microcephaly hypotonia MR round face |
|
|
What is the genetic basis of Wilms tumor?
|
deletion 11p-
|
|
|
What is the genetic basis of retinoblastoma?
|
deletion 13q-
|
|
|
What is the Lyon hypothesis?
|
there is inactivation of one of the X chromosomes in women, thus making them mosaics
|
|
|
What gene inactivates one of the x chromosomes?
|
Xist gene- this coats the inactive X chromosome with non coding DNA
|
|
|
The Y chromosome determines male sex, regardless of the number of X's
|
neat!
|
|
|
Where is the SRY gene?
|
this is on the short arm of the Y chromosome
|
|
|
What is Klinefelters syndrome?
|
this is male hypogonadism that occurs when there are 2 or more X chromosomes, and 1 or more Y chromosomes
|
|
|
What is the most common genotype for klinefelters?
|
47XXY
|
|
|
What is the main causes of Klinfelters?
|
parental and maternal nondisjunction
|
|
|
What are the characteristics for Klinefelters syndrome?
|
eunuchoid body type
long legs hypogonadism low IQ |
|
|
What tumors are klinfelters at risk for?
|
extragonadal germ cell tumors
|
|
|
What body is found in the genes of Klinfelters?
|
Barr Body
|
|
|
What is the phenotype of XYY syndrome?
|
normal, excessively tall
severe acne |
|
|
What is Turner Syndrome?
|
Complete or partial monosomy of the X chromosome-
hypogonadism females |
|
|
Are 45, X viable? (turner syndrome)
|
no, 99% abort by 20 weeks
|
|
|
What are the characteristics of Turner syndrome for the ones that are born?
|
Peripheral lymhpedema
cystic hygroma (big neck lymphedema) Webbed neck short stature |
|
|
What are the Adult symptoms of Turner syndrome?
|
Broad chest
pigmented moles (many) Coarctation of aorta Wide carrying angle of arms Primary amenorrhea infertile streak ovary |
|
|
What is a true hermaphrodite?
|
ovary on one side, tests in other
|
|
|
What are the genetics in a true hermaphrodite?
|
46,XX in half
SRY gene in most Often mosaics |
|
|
What is female pseudohermaphroditism?
|
Genetic female with ovaries, but male external genitalia
|
|
|
What is the pathogenesis of female pseudohermaphroditism?
|
congenital adrneal hyperplasia leads to a 21 hydroxylase deficiency.
excess androgens during embryogenesis |
|
|
What is male pseudohermaphroditism?
|
Y chromosomes and testes,
with external genitalia that are female |
|
|
What causes male pseudohermaphroditism?
|
defective androgen receptor
|
|
|
What is the most common presentation of male pseudohermaphroditism?
|
testicular feminization
|
|
|
How is male pseudohermaphroditism inherited?
|
X linked recessive
|
|
|
What is the adult presentation of male pseudohermaphroditism?
|
primary amenorrhea
normal breasts external female genitals no pubic or axillary hair no uterus |
|
|
What are the characteristics of noncoding region expansions?
|
loss of function
protein synthesis is suppressed |
|
|
What are the characterstics of coding regions expasions?
|
usually involved CAG repeats
|
|
|
What is an anticipation noncoding expansions
|
this is increasing expression or severity with each generation
|
|
|
What are premutation noncoding expansions?
|
multiple tandem repeats of 3 nucleotide sequences present in carriers
|
|
|
What is the inheritance of fragile X syndrome?
|
X linked, recessive
|
|
|
What gene is mutation in fragile X syndrome?
|
FMR-1 gene
|
|
|
What is the fragile site in fragile X syndrome?
|
chromosome appears brokken- found in long repeating sequences of 3 nucelotides CGG
|
|
|
What are the clinical signs of fragile X syndrome?
|
mentally retarded
Long face macro-orchidism (large testes) |
|
|
How does fragile X syndrome change with generations?
|
it gets worse- anticipation
|
|
|
How does fragile X syndrome affect females?
|
women can be mildly retarded, with primary ovarian insufficiency
|
|
|
Can there be male carriers of fragile X syndrome?
|
yes there can be
|
|
|
What chromosome does the FMR1 gene lie on? for fragile X syndrome
|
Xq17.3
|
|
|
What happens in fragile X syndrome genetically?
|
there are many CGG repeats in a UTR of Xq17.3
|
|
|
What does FMR1 code for?
|
FMRP- a protein abundant in the brain and testes
|
|
|
What happens in FMR1 female carriers?
|
premature ovarian failure
|
|
|
What is FXTAS?
|
fragile X syndrome associated tremor/ataxia syndrome. occurs in 30% of carrier men
|
|
|
What is the inheritance of a mitochondrial disease ?
|
mitochondria comes from moth
mothers transmit to son and daughter sons do not transmit |
|
|
What are the two examples of mitochondrial linked diseases?
|
Leber hereditary optic neuropathy
MELAS (mitchondrial encephalopahy, lactic acidosis, stroke like episodes) |
|
|
What is the presentation of Leber hereditary optic neuropahty?
|
progressive bilateral loss of central vision
|
|
|
Which parent do you get angelman syndrome from?
|
the mother
|
|
|
Which parent do you get prader willi from?
|
the dad
|
|
|
What is the clinical presentation of Prader Willi?
|
MR
short severe obesity Hypogonadism |
|
|
What are the genetics of prader willi?
|
del 15 q11q13- from Father
|
|
|
What are the clinical signs of Angelman syndrome?
|
happy puppet syndrome
MR Ataxia laughing |
|
|
What are the genetics of angelman syndrome?
|
deletion 15
inherited from mother INactive UBE3A from father (got imprinted over) |
