Genatics Flashcards
Cystic fibrosis :
A. Chromosome 7 long q arm
B. Chromosome 7 short p arm
C. Chromosome 7 short q arm
D. Chromosome 7 long p arm
Answer: A
Autosomal recessive, Cystic Fibrosis Transmembrane conductance Regulator CFTR gene found on the long (q) arm of chromosome 7 resulting in a dysfunctional chloride channel on the apical membrane of cells.
baby 8 month old breastfeed for 6 month normally. He devolved vomiting and jaundice after fruit juice. What component in the juice the baby is allergic to?
A. Glucose
B. Fructose
C. Sucrose
D. Galactose
E. Phenylalanine
Answer: b
Hereditary fructose intolerance due to deficiency of fructose-1,6-biphosphate aldolase b in the liver.
Hereditary galactosemia is among the most common carbohydrate metabolism disorders and can be a life-threatening illness during the newborn period . galactose-1-phosphate uridyltransferase (GALT) deficiency is the most common enzyme deficiency that causes hypergalactosemia.Removing lactose largely eliminates the toxicity associated with newborn disease, but long-term complications routinely occur.
Failure of obliteration of pharyngeal arch 2,3,4 leads to?
A. Cervical cyst
B. Branchial fistula
C. Ectopic thymus
D. Parathyroid
Answer: b
Explanation: 2nd through 4th clefts form temporary cervical sinuses, which are obliterated by proliferation of 2nd arch mesenchyme. Failure of obliteration leads to branchial cleft cyst within lateral neck.
Child less than 50 percentile, polyuria, constipation, low na, k, cl, where is the primary defect?
A. Na, cl channel
B. K chanel
C. H+ reabsorption
D. H+ secretion
Answer: a
A case of barrter syndrome :
autosomal recessive renal tubular disorders characterized by hypokalemia, hypochloremia, metabolic alkalosis, and hyperreninemia with normal blood pressure. The underlying renal abnormality results in excessive urinary losses of sodium, chloride, and potassium.
https://www.slideshare.net/mobile/azadhaleem/renal-tubular-acidosis-48018253
The most common chromosomal abnormality in a new infant ?
Down syndrome (Trisomy 21)
Most common abnormality of autosomal chromosomes.
Turner Features:
Answer: thick neck
Turner syndrome
Usually (>95%), Turner syndrome results in early miscarriage and is increasingly detected by ultrasound antenatally when fetal oedema of the neck, hands or feet or a cystic hygroma may be identified.
Treatment is with :
Growth hormone therapy
Estrogen replacement for development of secondary sexual characteristics at the time of puberty (but infertility persists).
In about 50% of girls with Turner syndrome, there are 45 chromosomes, with only one X chromosome. The other cases have a deletion of the short arm of one X chromosome, an isochromosome that has two long arms but no short arm, or a variety of other structural defects of one of the X chromosomes. The presence of a Y chromosome sequence may increase the risk of gonadoblastoma.
Turner syndrome , chromosomes ?
45 XO
Which of the following diseases has Mendelian mode of inheritance?
Answer: Alpha thalassemia
Autosomal recessive Mendilian inheritance example? Thalassemia*
Mode of inheritance of neurofibromatosis ?
Answer: Autosomal dominant
Explanation: Neurofibromatosis type 1 (NF1) and type 2 (NF2) are neurocutaneous disorders inherited as autosomal dominant genetic syndromes
X- linked ressesive
See the pic
Minimal probability of a baby getting beta thalassemia from carrier parents? A:0% , B:25%, C:50%, D:75%, E:100% Answer:B both 50% 25% affected - parents are carrier :- 25% - Unaffected Carrier Explanation: If both members of a couple are carriers (or heterozygotes) for this mutation, each of their offspring has a 25% chance of being affected (Nelson Essentials of Pediatrics 7th Ed, 2015)
14 years old boy comes to your clinic with swollen lips. He has similar episodes since 3 or 5 years. Deficiency of which of the following caused his presentation?
A. Factor D
b.Anaphylatoxin inhibitor
C. C1 esterase inhibitor
Answer: C
Hereditary angioedema is an autosomal dominant disease caused by low levels of the plasma proteins C1 inhibitor (C1-INH).
What is the inheritance mode of fanconi anaemia?
Answer: Autosomal recessive
What is the gene responsible for neurofibromatosis?
➢ The NF1 (peripheral neurofibromatosis or von Recklinghausen disease) gene is cytogenetically located on the long (q) arm of chromosome 17, band q11.2 (17q11.2). The NF1 gene encodes for a cytoplasmic protein called neurofibromin 1, which is a ras -GTPase–activating protein that suppresses tumor growth, primarily by inhibiting ras activity.
➢ The gene for NF2 (bilateral acoustic neurofibromatosis or central neurofibromatosis) is cytogenetically located on the long (q) arm of chromosome 22, band q12.2 (22q12.2). The NF2 gene codes for the protein neurofibromin 2, also called merlin or schwannomin.
A child came to you with Café au lait spots in face and neck. Which of the following features can strengthen your diagnosis?
A. Port-wine stain
b. Axillary freckling.
Answer: B
Clinical diagnosis requires the presence of at least 2 of 7 criteria to confirm the presence of NF1.
The 7 clinical criteria used to diagnose NF1 are as follows, in the absence of alternative diagnoses:
● Six or more café-au-lait spots or hyperpigmented macules =5 mm in diameter in prepubertal children and 15 mm postpubertal
● Axillary or inguinal freckles (>2 freckles)
● Two or more typical neurofibromas or one plexiform neurofibroma
● Optic nerve glioma
● Two or more iris hamartomas (Lisch nodules), often identified only through slit-lamp examination by an ophthalmologist
● Sphenoid dysplasia or typical long-bone abnormalities such as pseudarthrosis
● First-degree relative (eg, mother, father, sister, brother) with NF1
NF2: meningioma, schwannoma, glioma, neurofibroma, posterior subcapsular lenticular opacities accompanied by external signs: hearing loss, ringing in the ears, and balance problems associated with vestibular nerve lesions, visual deficits and cranial nerve palsies.
child with developmental delay and constipation. Labs: low Na , low K and low ..?? what is the most likely diagnosis ?
A. CAH
B. Congenital chloride diarrhea
C. other choices include syndromes
Answer:?
Barter syndrome
some hypokalemic pt develope rhabdomyolysis especially following exercises
hpokalemia :
1- slow the gastrointestinal motility = constipation , and if potassium less than 2,5 meq/L can cause paralytic ileus
2- impaire bladder function causing urinary retintion
3- can cause polyurea secondary to nephrogenic DI
chronic hypokalemia :
1-kidney damage ( interstitial nephritis, renal cyst)
2- poor growth
What is characterised about fragile x syndrome?
A. Obesity
B. Macrogonadisim
C. Smal
Answer: B
Fragile X syndrome is the commonest familial form of learning difficulties and the second most common genetic cause of severe learning difficulties after Down syndrome.
FEATURES :
A)Characteristic craniofacial finding (large head,prominent forehead, jaw,ear)
B)Characteristic neurobehavioral profile including (mental retardation, autism spectrum disorder, pervasive developmental disorder )
C)Macro-orchidism
D)Mild connective tissue disorder including (joint laxity,patulous eustachian tubes ,mitral valve prolapse)
What come with Turner syndrome ?
A.Hypothyroid
B.DM
C.Addison’s
Answer: A
5 years old, with recurrent infection, greasy diarrhea, slow growing, he’s jaundiced with positive sweat chloride test?
Cystic Fibrosis
To confirm down syndrome ?
choroinc villous sampling✅
