Term
| What is the lifetime frequency of genetic diseases? |
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Definition
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Term
| What percent of people under 25 have 'genetic disease'? |
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Definition
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Term
| How many abnormal genes does the average person have? |
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Definition
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Term
| What are the three different classifications of genetic disorders? |
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Definition
| chromosomal, single gene (mendelian inheritance and nontraditional inheritance), and complex multigenic/multifactorial |
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Term
| What is the #1 known cause of 1st trimester miscarriages? |
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Definition
| chromosomal/cytogenic abnormalities |
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Term
| What percent of the population has a chromosomal abnormality? |
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Definition
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Term
| How many 1st trimester abortions, stillbirths, and live births have a chromosomal abnormality? |
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Definition
| 60% of 1st trimester SAB, 6% of stillbirths, .6% of livebirths |
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Term
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Definition
| dark strips on chromosomes in a karytype caused by Geimsa stain |
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Term
| What are indications for cytogenetic studies? |
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Definition
| birth defects/malformations, stillborn neonate/spontaneous abortus, AMA, both parents in a couple with > 2 pregnancy losses, unbalanced chromosomes for both parents, tumors |
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Term
| What are the two types of structural abnormalities? |
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Definition
1) balanced rearrangement- correct amount of genetic material but rearranged. Phenotype is normal.
2) unbalanced: loss/gain of genetic material. Phenotype is abnormal. |
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Term
| Name examples of balanced cytogenetic disorders. |
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Definition
| translocations, inversions |
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Term
| What are some examples of unbalanced cytogenetic disorders? |
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Definition
| translocations, deletions, duplications, isochromosome |
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Term
| Describe the two types of translocations. |
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Definition
1)reciprocal- translocation between 2 chromosomes. Can be balanced or unbalanced.
2) robertsonian: a fusion of two acrocentric chromosomes. Can be balanced or unbalanced |
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Term
| What is the incidence of reciprocal translocation? |
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Definition
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Term
| What is the incidence of Robertsonian translocation? |
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Definition
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Term
| Which chromosomes are acrocentric and thereby can undergo Robertsonian tranlocations? |
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Definition
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Term
| What are the two types of inversions? |
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Definition
paracentric: involves one arm of the chromosomes
pericentric: involves both arms of the chromosome |
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Term
| A ring chromosome is due to what type of mutation? |
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Definition
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Term
| What is the frequency of deletion mutations? |
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Definition
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Term
| What is the incidence of deGeorge syndrome? |
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Definition
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Term
| What are the symptoms of diGeorge syndrome and where is the deletion? |
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Definition
C: cardiac (TOF, TA)
A: abnormal face
T: thymus aplasia
C: cleft palate
H: hypocalcemia
22: deletion of 22q |
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Term
| What/where is the mutation that causes Cri du Chat? |
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Definition
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Term
| T/F A few signs of Cri du Chat are epicanthal folds, mental retardation, and a heart defect. |
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Definition
| True! also, the high pitched cry, hypertelorism, and microcephaly |
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Term
| T/F Duplications are more harmful than deletions. |
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Definition
| False, the opposite is true |
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Term
| What is an Isochromosome? |
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Definition
| loss of one arm of chromosome with duplication of the other arm |
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Term
| What percent of Turner's is due to an Isochromosome? |
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Definition
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Term
| What do you call a cell that has just 1 or 2 extra or missing chromosomes? |
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Definition
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Term
| What do you call it when a cell has chromosome numbers that are mutliples of the haploid number of chromosome (like 3n or 4n, instead of the normal 2n)? |
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Definition
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Term
| What causes Triploidy? What is the incidence of livebirths with triploidy? |
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Definition
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Term
| T/F Down syndrome patients are at a lower risk for Alzhiemer's. |
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Definition
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Term
| Which cancer are Down's syndrome patients at a higher risk for? |
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Definition
| ALL (acute lymphoblastic leukemia) |
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Term
| T/F Down's syndrome is the #1 cause of mental retardation. |
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Definition
| False, Down's syndrome is the #1 cause of GENETIC mental retardation. Most MR is idiopathic. |
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Term
| What genetic mutations cause down's? |
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Definition
95% is due to Trisomy 21
3% is due to unbalanced translocations |
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Term
| What's your risk of having a Down's syndrome baby at 35? 40? 50? |
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Definition
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Term
| What percent of Down's syndrome patients have heart defects? |
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Definition
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Term
| What are the symtoms of trisomy 18 (Edwards Syndrome)? |
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Definition
| heand clench, omphalocele, heart defect, mental retardation, rocker bottom feet, horseshoe kidneys, death by 1 yoa |
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Term
| What's the incidence of Edwards? |
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Definition
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Term
| T/F The risk for ALL aneuploidies incresaes with maternal age. |
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Definition
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Term
| What are the symptoms of Trisomy 13 (Patau Syndrome)? |
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Definition
| midline defects (cyclopia, heart defects, holoprosencephaly, cleft lip, neural tube defects, cutis aplasia), post axial polydactyly and death by 1 yr |
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Term
| What is the incidence of Patau? |
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Definition
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Term
| What are the characteristics of Turner's syndrome? |
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Definition
| short stature, webbed neck, shield chest, increased cubitus carrying angle, streak ovaries, coarctation of aorta, infertility with primary amenorrhea |
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Term
| What are the characteristics of klinefelter's (XXY)? |
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Definition
| tall, thin, delayed secondary sexual development, hypogonadism, infertility (decreased testosterone), gynecomastia |
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Term
| What is the incidence of Klinefelter's? |
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Definition
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Term
| Describe XYY syndrome characteristics. |
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Definition
| tall stature, increased behavioral problems |
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Term
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Definition
XYY: paternal meitoic nondisjunction
XXX: maternal meiotic nondisjunction |
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Term
| What are the features of XXX syndrome? |
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Definition
| increased behavioral/learning problems |
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Term
| What % of the pediatric and adult population have multifactorial conditions? |
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Definition
10% of pediatric population
60% of adult population |
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Term
| For a multifactorial condition, the % contribution from genetics is termed ____. |
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Definition
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Term
| T/F Phenotypic traits, like height, IQ, and blood pressure, are multifactorial conditions. |
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Definition
| true, observed in populations as unimodal, normally distributed, gaussian curves |
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Term
| Multifactorial conditions that are either present or absent are termed ___. |
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Definition
| discontinuous or discrete |
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Term
| What are the two broad categories that multifactorial disorders are broken up into? |
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Definition
| common adult diseases (diabetes, obesity, schizophrenia, CAD) and congenital malformations |
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Term
| What 5 types of congenital malformations are classic multifactorial disorders? |
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Definition
| congenital heart disease, cleft lip/palate, club foot, congenital hip dislocation, pyloric stenosis |
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Term
| Because multifactorial conditions are a genetic category of exclusion, what must you look at/rule out to make sure it is a MF condition? |
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Definition
| inheritance pattern is not Mendelian, cytogenetics are normal and disorder is isolated (non-syndromic) |
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Term
| Recurrence Risks in multifactorial disorders can vary with... |
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Definition
| severity of disease, sex of affected proband, and number of affected individuals in a family |
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Term
| Incidence of Hypertrophic pyloric stenosis? |
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Definition
| 1/500 births, higher incidence in first born and males> females (5:1) |
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Term
| What's the incidence of NTDs in the US? |
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Definition
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Term
| What's the incidence of cleft palate? cleft lip and palate? |
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Definition
1/2000 cleft palate
cleft lip and cleft palate is 1/1000 |
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Term
| Which populations are at higher risk for cleft lip and palate? |
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Definition
native americans>asians>caucasians
males> females (3:2) |
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Term
| What's the incidence of mild congenital heart disease? moderate-severe congenital heart disease? |
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Definition
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Term
| What environmental factor can cause congenital heart disease? |
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Definition
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Term
| What are the recurrence rates for parents who have 1 child with an MF disorder? 2 children? 3 children? 4 children? |
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Definition
| 3-5%, 5-10%, 10-20%, and 20-40% |
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