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Biochemistry
FA complete review part 3 Genetics and Lab techniques
| Question | Answer |
|---|---|
| Which lab procedure is used to amplify a desired fragment of DNA? | PCR |
| What are some examples of diseases in which PCR is a good diagnostic tool? | Neonatal HIV, herpes encephalitis |
| What are the three steps of PCR mode of action? | 1. Denaturation 2. Annealing 3. Elongation |
| Describe the Denaturation process in PCR. | DNA is heated to ~95 C to separate the strands |
| Annealing in PCR refers to: | Denatured sample to cool off to ~55 C |
| What is added to the DNA sample in the Annealing process of PCR? | DNA dimers, a heat-stable DNA polymerase (Taq), and deoxynucleotide triphosphates (dNTPs) |
| What is the Elongation step of PCR? | Temperature is increased to ~72 C. DNA pol attaches dNTPs to the strand to replicate the sequence after each primer |
| The phrase "heating and cooling cycles until the DNA sample size is sufficient" can be a reference to which lab technique? | PCR |
| What is CRISPR/Cas9? | A genome editing tool, derived form bacteria. Composed of an endonuclease and a guide RNA sequence that binds to a complementary target DNA sequence. |
| What is the endonuclease in CRISPR/Cas9? | Cas9, which cleaves dsDNA |
| Southern Blot identifies _____________. | DNA |
| Northern Blot identifies _____________. | RNA |
| Western blot identifies ______________. | Protein |
| What is used prior to Southern blot plotting, to separate DNA small pieces? | Gel electrophoresis |
| What is the filter used in Southern blotting? | Radiolabeled DNA probe that recognizes and anneals to its complementary strand |
| Cleaved DNA --> Gel electrophoresis --> Filter placement --> visualized DNA on film. Describes which lab technique? | Southern blotting |
| What is the main procedural difference between Northern and Southern blotting? | RNA sample in Northern blotting is ELECTROPHORESED. |
| Northern blotting is useful when studying ______ levels, which are reflective of ____________________. | mRNA levels ===== Gene expression |
| Labeled antibody used | Western blot |
| Once protein is separated by electrophoresis, it is transferred to a ________________, in western blotting? | Membrane |
| Which blotting technique identifies DNA-binding proteins? | Southwestern blot |
| Which are them most common DNA-binding proteins identified by SW blot? | Transcription factors |
| What kind of probe is used in Southwestern blot? | Labeled oligonucleotide probes |
| What assessed with Flow Cytometry? | Size, granularity, and protein expression of an individual cell |
| In a scatter plot of a flow cytometry, what can be assumed for the cells (dots) in the Lower Left quadrant? | They are negative for both tested labeled antibodies/proteins |
| What are some common conditions for which flow cytometry is often used? | 1. Work up of hematologic abnormalities (paroxysmal nocturnal hemoglobinuria, fetal RBCs in mother's blood) 2. Immunodeficiencies (CD4 cell count in HIV) |
| What is the use of Microarrays? | Profile gene expression levels of thousands of genes simultaneously to study certain diseases and treatments |
| What are some important application of Microarrays? | Genotyping, clinical genetic testing, forensic analysis, cancer mutations, and genetic linkage analysis |
| Thousands of nucleic acid sequences are arranged in grids on glass or silicon. DNA or RNA probes are hybridized to chip, and scanner detects relative amounts of complementary binding. | Microarrays |
| What is commonly detected with Microarrays? | Single nucleotide polymorphisms (SNPs) and Copy Number Variations (CNVs) |
| What laboratory technique is used to ID presence of a specific antigen or antibody in the patient's blood? | ELISA |
| What technique involves the use of an antibody liked to an enzyme. | ELISA |
| What is more specific, Western blot or ELISA? | Western blot |
| What is detected by a Direct ELISA? | Antigen |
| What is detected by an Indirect ELISA? | Antibody |
| Karyotyping: | Process in which metaphase chromosomes are stained, ordered, and numbered according to morphology, size, arm-length ratio, and banding pattern |
| In which phase does Karyotyping takes place? | Metaphase |
| What is the main use for Karyotyping? | Diagnose chromosomal imbalances |
| What are examples of chromosomal imbalances detected by Karyotyping? | Autosomal trisomies and sex chromosome disorders |
| What is FISH used for? | Used for specific localization of genes and direct visualization of chromosomal anomalies at the molecular level |
| What types of anomalies are visualized with FISH? | Microdeletion, Translocation, and Duplication |
| How is a Microdeletion depicted by FISH? | NO florence on a chromosome compared to fouchtre dat the same locus on the second copy of the chromosome |
| Translocation by FISH demonstrates: | Floucerence signal that corresponds to one chromosome found in a different chromosome |
| Second copy of a chromosome, resulting in a trisomy or tetrasonomy, describes: | Duplication seen with FISH |
| What is the first step in molecular cloning? | Isolate eukaryotic mRNA (post-RNA processing) of interest. |
| Overall, what is the cloned DNA? | That DNA material produced from surviving bacteria after the integration of recombinant plasmid and grow in antibiotic medium |
| What are the Transgenic strategies in mice? | 1. Random insertion of gene into mouse genome 2. Targeted insertion or deletion of gene through homologous recombination with mouse gene |
| What is another way to refer to a Random insertion of a gene? | Constitutive |
| Targeted insertion into a gene is known as _________________. | Conditional |
| Knock-out refers, in terms of gene expression modifications? | Removing a gene, taking it out |
| Inserting a gene in gene expression, can be addressed as ___________. | Knock-in |
| How does the Cre-lox system works? | Can inducibly manipulate gene at specific developmental points |
| What is RNA interference? | dsRNA is synthesized that is complementary to the mRNA sequence of interest. When transfected into human cells, dsRNA separates and promotes degradation of target mRNA "knocking down" gene expression |
| What is codominance? | Both alleles contribute to the phenotype of the heterozygote |
| Genetic condition in which the two alleles of a heterozygote are presented in the phenotype. | Codominance |
| Variable expressivity: | Patients with the same genotype have varying phenotypes |
| What are some examples of Codominance? | 1. Blood groups A, B, AB 2. Alpha 1-antitrypsin deficiency 3. HLA groups |
| The mild or varying differences in phenotype in persons with the same disease is known as ______________________________. | Variable expressivity |
| What would be the genetic term used for two people with exact same condition but different severity of the disease? | Variable expressivity |
| The fact not all the times of a gene mutation can cause the probable disease or condition is referred as: | Incomplete penetrance |
| What is Incomplete penetrance? | Not all individuals with a mutant genotype show the mutant phenotype. |
| What equation is used to predict the risk of expressing phenotype? | % penetrance x probability of inheriting genotype |
| One gene contributes to multiple phenotypic effects | Pleiotropy |
| What is Pleiotropy? | Genetic phenomenon one gene generates multiple or various different phenotypic effects |
| Why is PKU is an example of Pleiotropy? | Manifest with 1. light skin, 2. Intellectual disability, and 3. musty body odor. |
| What is anticipation? | Increased severity or earlier onset of disease in succeeding generations |
| What is a common example condition of anticipation? | Huntington disease |
| Trinucleotide repeat diseases often are associated with which genetic phenomenon? | Anticipation |
| What is Loss of Heterozygosity? | If a patient inherits or develops a mutation in tumor suppressor gene, the complementary allele must be deleted/mutated before cancer develops |
| Which type of genes express Loss of Heterozygosity principle? | Tumor suppressor genes |
| Is it possible to observe the principle of Loss of Heterozygosity in oncogenes? | Not possible |
| Conditions that present Loss of Heterozygosity? | Retinoblastoma and the "two-hit hypothesis", Lynch syndrome (HNPCC), and Li-Fraumeni syndrome |
| When is Dominant negative mutation presented? | A heterozygous produces a nonfunctional altered protein that also prevents the normal gene product from functioning |
| A altered protein (nonfunctional) that also prevents normal genes/proteins from working. | Dominant negative mutation |
| What is Linkage disequilibrium? | Tendency for certain alleles at 2 linked loci to occur together more or less often than expected by chance |
| A change in tendency in a population is referred in genetic principle as ________________________________. | Linkage disequilibrium |
| What are the two main types of Mosaicism? | 1. Somatic 2. Gonadal |
| Presence of genetically distinct cell lines in the same individual | Mosaicism |
| What is Somatic mosaicism? | Mutation arises from mitotic errors after fertilization and propagates through multiple tissues or organs |
| What is another term used for gonadal mosaicism? | Germline mosaicism |
| Mutation only in egg or sperm cells | Gonadal (germline) mosaicism |
| When is encourage to suspect Gonadal mosaicism? | If parents and relatives do not have the disease |
| What is a very common example of a condition presenting with Mosaicism? | McCune-Albright syndrome |
| What condition is due to mutation to G-protein signaling? | McCune-Albright syndrome |
| How is possible to have a non-lethal McCune-Albright syndrome patient? | If the condition presents mosaicism as the mutation occur after fertilization |
| Mitotic errors after fertilization affecting multiple tissues or organs? | Somatic mosaicism |
| What is Locus heterogeneity? | Mutations at different loci can produce a similar phenotype |
| What is a common example of Locus heterogeneity? | Albinism |
| Mutations at different loci causing the same disease | Locus heterogeneity |
| What is Allelic heterogeneity? | Different mutations in the same locus produce the same phenotype |
| In locus (X), there are 3 different mutations, which produce the same disease. This genetic principle is known as: | Allelic heterogeneity |
| B-thalassemia is a condition presting which genetic principle? | Allelic heterogeneity |
| What is Heteroplasmy? | Presence of both normal and mutated mtDNA, resulting in variable expression in mitochondrially inherited disease |
| Which type of inheritance always presents with Heteroplasmy? | Mitochondrial inheritance |
| Heteroplasmy gives rise to another genetic principle which is _______________. | Variable expression |
| What is Uniparental disomy? | Offspring receives 2 copies of a chromosome from 1 parent and no copies fro the other parent. |
| What is indicated by Heterodisomy? | Meiosis I error |
| Which form of disomy is due to a Meiosis II error? | Isodisonomy |
| When should a UPD (uniparental disomy) be suspected? | Individual with a recessive disorder when only one parent is a carrier |
| What are the two most common examples of UPD? | Prader-Willi and Angelman syndromes |
| What are the assumptions of the Hardy-Weinberg Law? | 1. No mutation occuring at the locus 2. Natural selection is not occuring 3. Completely random mating 4. No net migration 5. Large population |
| What is the equation of the sum of frequencies in H-W law? | (p)2 + 2pq +(q)2 = 1 |
| What is the frequency of X-liked recessive disease in males? | q |
| What is the frequency of X-linked recessive disease in females? | q2 |
| Definition of Imprinting. | One gene copy is silenced by methylation, and olvy the other copy is expressed --> parent-of - origin effects |
| When does Prader-Willi syndrome occurs? | When paternal allele is deleted or mutated |
| Which condition is seen with maternally derived genes silenced? | Prader-Willi syndrome |
| What are the signs and symptoms seen in Prader Willi syndrome? | Hyperphagia, obesity, intellectual disability, hypogonadism, and hypotonia |
| Which chromosome is affected in Prader-WIlli syndrome? | Chromosome 15 of paternal origin |
| Which gene is silenced in Angelman syndrome? | Paternally derived UBE3A |
| Disease occurs when the maternal alleles is deleted or mutated. Dx? | Angelman syndrome |
| What are the signs and symptoms of Angelman disease? | Seizures, Ataxia, severe intellectual disability, inappropriate laughter |
| Which is the involved chromosome in Angelman syndrome? | UBE3A on maternal copy of chromosome 15 |
| Maternal uniparental disomy. Dx? | Prader-Willi syndrome |
| Paternal uniparental disomy. Dx? | Angelman syndrome |
| What mode of inheritance is seen with defects in structural genes? | Autosomal Dominant |
| What are some genetic principles strongly associated with Autosomal dominant mode of inheritance? | 1. Pleiotropic 2. Variably expressive |
| One affected parent of an autosomal dominant condition, has _____% of children affected. | 50 |
| 2 carries of an Autosomal recessive disorder produced (Offspring): | - 25% will be affected (homozygous) - 50% will be carriers - 25% no carriers and unaffected |
| Enzyme deficiencies are often due to what type of mode of inheritance? | Autosomal recessive |
| Which are more severe conditions, autosomal dominant or autosomal recessive? | Autosomal recessive |
| What is the probability of an unaffected individual to be a carrier, if he or she has an affected sibling? | 2/3 |
| What is a common increased risk for autosomal recessive disorders? | Consanguineous families |
| What kind of inheritance mode has no male-to-male transmission? | X-linked recessive |
| What chance (%) sons of heterozygous mothers have of being affected with an X-linked recessive disease? | 50% |
| X-linked recessive usually are more severe in ____________. | Males |
| A female needs to be ___________________, for an X-linked recessive condition in order to be affected. | Homozygous |
| X-linked recessive inheritance pattern ______________ generations. | Skip |
| What are common examples of X-linked dominant disorders? | Fragile X syndrome, Alport syndrome, and Hypophosphatemic rickets |
| Mother affected with an X -linked dominant disorder has: | Transmission to 50% of daughters and sons |
| Fathers tramnit to ___________ daughters in a X-linked dominant inheritance pattern. | ALL |
| What is a commonly used Mitochondrial Inheritance condition? | Leber hereditary optic neuropathy (LHON) |
| Which parent is the only one that can transmit a Mitochondrial inheritance disease? | Mother |
| How many offspring of an affected mother with an Mitochondrial inheritance disease, are affected? | All offspring |
| Why is the variable expression in Mitochondrial inheritance diseases? | Due to Heteroplasmy |
| What is often seen in Mitochondrial myopathies? | Myopathy, lactic acidosis, and CNS disease; secondary to failure in oxidative phosphorylation |
| What is a common biopsy finding in MELAS syndrome? | "ragged red fibers" |
| What gives MELAS syndrome bx findings it "ragged red fiber" look? | Accumulation of diseased mitochondria in the subsarcolemmal of the muscle fiber |
| Cell death of optic nerve neurons ---> subacute bilateral vision loss in teens/young adults (permanent damage). Dx? | Leber hereditary optic neuropathy |
| List of Autosomal Dominant diseases: | 1. Achondroplasia 2. ADPKD 3. Familial adenomatous polyposis (FAP) 4. Familial Hypercholesterolemia 5. Hereditary Hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome) 6. Hereditary spherocytosis 7. Huntington disease 8. Li-Fraumeni syndrome 9. Marfan syndrome 10. MEN 11. Myotonic muscular dystrophy 12. NF type I and type II 13. Tuberous sclerosis 14. von Hippel-Lindau disease |
| What are the MC Autosomal recessive disorders? | 1. Oculocutaneous albinism 2. ARPKD 3. Cystic fibrosis 4. Friedreich ataxia 5. Glycogen storage diseases 6. Hemochromatosis 7. Kartagener syndrome 8. Hurler disease 9. PKU 10. Sickle cell anemia 11. Sphingolipidoses (except Fabry disease) 12. Thalassemias 13. Wilson disease |
| Which sphingolipidoses disease is not AR inheritance? | Fabry disease |
| What is the defect in Cystic Fibrosis? | CFTR gene on chromosome 7; commonly a deletion of Phe508 |
| Which is the most common lethal genetic disease of Caucasian population? | Cystic fibrosis |
| What is the role of the CFTR? | Encodes an ATP-gated Cl- channel that secretes Cl- in lungs and GI tract, and reabsorbs Cl- in sweat glands |
| In Cystic fibrosis, the CFTR mutation causes? | Misfolded protein --> protein retained in RER and not transported to cell membrane, cause a decrease in Cl- secretion |
| The misfolded CFTR protein causes electrolytic imbalance in CF because: | Protein is retain in RER and it cannot be transported to cell membrane, leading to retention of Cl-. |
| Increased Cl- concentration in pilocarpine-induced sweat test is diagnostic of: | Cystic fibrosis |
| MCC of recurrent pulmonary infections in a child with Cystic fibrosis? | S. aureus infection |
| What is the most common infectious agent causing recurrent pulmonary infections in adults with CF? | P. aeruginosa |
| What is the described pattern in CXR of CF patient? | Reticulonodular pattern; Opacification of sinuses |
| What are some respiratory complications or associated conditions of Cystic fibrosis? | Recurrent pulmonary infections, allergic bronchopulmonary aspergillosis, chronic sinusitis and bronchiectasis |
| What are the GI complications seen with Cystic Fibrosis? | Pancreatic insufficiency, malabsorption with steatorrhea, fat-soluble vitamin deficiencies, biliary cirrhosis, and liver disease |
| Absence of vas deferens, MCC of infertility in males with: | Cystic fibrosis |
| What treatment is used in CF in order to facilitate mucus clearance? | Chest physiotherapy, albuterol, aerosolized dornase alfa (DNAse) and hypertonic saline |
| Why is azithromycin used in CF treatment? | Anti-inflammatory |
| What can be used to slow the progression of CF pathogenesis? | Ibuprofen |
| In CF patients with Phe508 deletion, what are the treatment options? | Combination of Lumacaftor and Ivacaftor |
| What is X-inactivation (lyonization)? | One copy of female X chromosome forms a transcriptionally inactive Barr body |
| List of X-linked recessive disorders: | 1. Ornithine transcarbamylase deficiency, 2. Wiskott-Aldrich syndrome, 3. Ocular albinism, 4. G6PD deficiency, 5. Hunter syndrome, 6. Bruton agammaglobulinemia, 7. Hemophilia A and B, 8. Lesch-Nyhan syndrome, 9. Duchenne (and Becker) muscular dystrophy |
| Why are female carriers of an X-recessive disorder are variably affected? | It depends on which X chromosome was inherited (mutant vs normal) |
| What are 3 common Muscular dystrophies? | Duchenne, Becker, and Muscular dystrophy |
| Duchenne muscular dystrophy is due to _______________ mutation, leading to ________________ protein. | Frameshift; truncated or absent dystrophin |
| What is the mutated protein in Duchenne muscular dystrophy? | Dystrophin |
| How is the muscular weakness in Duchenne progresses? | Begins at Pelvic girdle muscles and moves superiorly. |
| What is a very common leg sign of Duchenne muscular dystrophy? | Pseudohypertrophy of calf muscles |
| Why is there pseudohypertrophy in calf muscles in Duchenne? | Fibrofatty replacement of muscle |
| What is the MCC of death in children younger than 5 years old with Duchenne muscular dystrophy? | Dilated cardiomyopathy |
| Which is the largest protein-coding human gene? | Dystrophin gene (DMD) |
| What is the main action of dystrophin? | Helps anchor muscle fibers, primarily skeletal and cardiac muscle |
| The loss of dystrophin leads to ----> | Myonecrosis |
| What are two labs results commonly elevated in Duchenne muscular dystrophy? | CK and aldolase |
| Gowers sign. Dx? | Duchenne muscular dystrophy |
| Patient uses upper extremities to help stand up. Sign? | Gowers sign |
| Non-frameshift deletions in dystrophin gene. Dx? | Becker muscular dystrophy |
| What is the nucleotide repeat of Myotonic dystrophy? | CTG |
| What are the clinical features of Myotonic dystrophy? | 1. Myotonia 2. Muscle wasting 3. Cataracts 4. Testicular atrophy 5. Frontal balding 6. Arrhythmia |
| What is Rett syndrome? | Sporadic disorder seen almost exclusively in girls |
| What are clinical manifestations of Rett syndrome? | REGRESSION in motor, verbal, and cognitive abilities; ataxia; seizures; growth failure; and stereotyped hand-wringing. |
| What condition is often associated with regression complications? | Rett syndrome |
| De novo mutation of MECP2 on X chromosome. Dx? | Rett syndrome |
| What is the mode of inheritance of Fragile X syndrome? | X-linked dominant |
| CGGn. Dx? | Fragile X syndrome |
| Trinucleotide repeat in FMR1 gene --> Hypermethylation. Dx? | Fragile X syndrome |
| What is the second most common cause of mental deficiency? | Fragile X syndrome |
| Common features of Fragile X syndrome? | Post-pubertal macroorchidism, long face with a large jaw, autism, and MVP. |
| What are the Trinucleotide repeat expansion diseases? | 1. Huntington disease 2. Myotonic dystrophy 3. Fragile X syndrome 4. Friedreich ataxia |
| CAGn. Dx? | Huntington disease |
| GAAn. Dx? | Friedreich ataxia |
| CTGn. Dx? | Myotonic dystrophy |
| What genetic principle is seen with Trinucleotide repeat expansion diseases? | Anticipation |
| Common autosomal trisomies? | Down, Edwards, and Patau syndrome |
| Trisomy 21. | Down syndrome |
| Trisomy 18 | Edwards syndrome |
| Trisomy 13 | Patau syndrome |
| Down syndrome common clinical features | Intellectual disability, flat facies, prominent epicanthal folds, single palmar crease, gap between 1st 2 toes, duodenal atresia, Hirschsprung disease, congenital heart disease, and Brushfield spots |
| What is the most common GI pathological features of Down syndrome? | Duodenal atresia and Hirschsprung's disease |
| Prominent epicanthal folds. Dx? | Down syndrome |
| What is epicanthal fold? | Skin fold of the upper eyelid covering the inner corner of the eye |
| What neurodegenerative condition is strongly associated with Down syndrome? | Early-onset Alzheimer disease |
| What hematologic malignancies are seen with higher recurrence in Down syndrome patients? | ALL and AML |
| What are the 5 A's of Down syndrome? | 1. Advanced maternal age 2. Atresia (duodenal) 3. Atrioventricular septal defect 4. Alzheimer disease (early onset) 5. AML/ALL |
| What is the most common cause of Down syndrome? | Meiotic nondisjunction |
| What is the mnemonic used to describe the clinical findings of Edwards syndrome? | PRINCE |
| What does PRINCE (mnemonic for Trisomy 18) stands for? | Prominent occiput, Rocker-bottom feet, Intellectual disability, Nondisjunction, Clench fists, low-set Ears, |
| Which trisomy is seen with micrognathia? | Edwards |
| What is the meaning of of micrognathia? | Small jaw |
| What are characteristic clinical findings of Patau syndrome? | Rocker-bottom feet, microphthalmia, microcephaly, cleft lip/palate, holoprosencephaly, Polydactyly, cutis aplasia, congenital heart disease, Polycystic kidney disease |
| Holoprosencephaly and microcephaly are common severe findings of _________________ syndrome. | Patau |
| Cleft lip/palate, Polydactyly, cutis aplasia, and microphthalmia are often seen with ______________________ syndrome. | Patau |
| If the nondisjunction occurs in Meiosis I, what is the total number of Trisomies produced? | 2 |
| If the nondisjunction happens during Meiosis II, how many trisomies are produced by the end of meiosis II? | 1 |
| n + 1 = | Trisomy |
| n - 1 = | Monosomy |
| How many trisomies and monosomies are produced in meiosis with a nondisjunction problem at Meiosis I? | 2 pairs of each |
| Which trisomy syndrome has all normal serum markers in the 2nd trimester? | Patau syndrome |
| Down syndrome serum marker in the 1st trimester shows an elevated __________________ level. | B-hCG |
| Edwards syndrome has all ___________________ serum markers. | Decreased |
| Examples of chromosome 3 genetic mutation: | von Hippel-Lindau disease and Renal cell carcinoma |
| Chromosome 4 mutations cause: | ADPKD due to PKD2, achondroplasia, and Huntington disease |
| Achondroplasia is due to a mutation in chromosome ___. | 4 |
| Which chromosome is mutated/defective in Huntington disease? | Chromosome 4 |
| What are common conditions due to chromosome 5 defects? | Cri-du-chat syndrome, and Familial adenomatous polyposis (FAP) |
| Hemochromatosis is due to a defective chromosome ___. | 6 |
| What are two conditions due to defective chromosome 7? | Williams syndrome and Cystic Fibrosis |
| What is the most common disease due to a mutation in chromosome 7? | Cystic fibrosis |
| Friedreich ataxia and Tuberous sclerosis are due to a ___________________________. | Chromosome 9 mutation |
| Examples of Chromosome 11 genetic conditions: | Wilms tumor, B-globin gene defects (SCD, B-thalassemia), and MEN 1. |
| Defective chromosome 13 produces: | 1. Patau syndrome 2. Wilson disease 3. Retinoblastoma (RB1) 4. BRCA2 |
| Imprinting conditions are due to a defect in chromosome ____. | 15 |
| Marfan syndrome is due to a defect in chromosome _____, which produces a defective ______________ (protein). | 15; fibrillin |
| Prader-Willi syndrome and Angelman syndrome are both due to a defect in which chromosome? | 15 |
| Alpha-thalassemia is due to chromosome ____ defect, and B-thalassemia is due to a chromosome _____ defect. | 16------alpha 11-------beta |
| Common conditions of mutated chromosome 16: | ADPKD due to PDK1 gene mutation, a-goblin gene defects, and Tuberous sclerosis (TSC2) |
| NF type 1, BRCA 1, and p53, all associated with which defective chromosome? | 17 |
| Genetic disorders caused by Chromosome 22 deficit? | NF type 2, and DiGeorge syndrome |
| 22q11. | DiGeorge syndrome |
| Which are common X chromosome genetic conditions? | Fragile X syndrome, X-linked agammaglobulinemia, Klinefelter syndrome (XXY) |
| XXY. Dx? | Klinefelter syndrome |
| What chromosomes are often associated with Robertsonian translocations? | 13, 14, 15, 21 and 22 |
| When does a Robertsonian translocation occurs? | When the long arms of 2 acrocentric chromosomes fuse at the centromere ant he 2 short arms are lost |
| What happens to the 2 short armes involved in a Robertsonian translocation? | They are lost |
| What are acrocentric chromosomes? | Chromosomes with centromeres near their ends |
| What is the result of unbalanced Robertsonian translocations? | Miscarriage, stillbirth, and chromosomal imbalance (Down and Patau syndromes) |
| Which trisomies are (rarely) due to Robertsonian translocations? | Patau and Down syndromes |
| Cry of a cat. Dx? | Cri-du-chat syndrome |
| Congenital deletion of short arm of chromosome 5. Dx? | Cri-du-chat syndrome |
| Cri-du-chat syndrome may be represented as: | 46, II or XY, 5p- |
| What is the most characteristic finding of Cri-du-chat syndrome? | High-pitched crying/meowing |
| Congenital microdeletion of long arm of chromosome 7. Dx? | Williams syndrome |
| The elastin gene is deleted in which genetic condition of defective chromosome 7? | Williams syndrome |
| What is the adjective use to describe the facial features of a patient with Williams syndrome? | "elfin"facies |
| What are some key clinical features of Williams syndrome? | 1. Distinctive "elfin" facies 2. Hypercalcemia (increased sensitivity to Vitamin D) 3. Well - developed verbal skills 4. Extreme friendliness with strangers, 5. CV problems |
| What CV conditions are seen with Williams syndrome? | Supravalvular aortic stenosis and Renal artery stenosis |
| What does an "elfin" facies referred to? | Face characteristic associated with elve-looking face |
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