Genetics

Question 1

4y boy 👖 + progressive proximal muscles weakness + waddling gait + delayed motor milestones + Gower sign when he was baby
Dx?
Invest.?

Answer 1

Duchenne muscular dystrophy .
* x-linked recessive So case note (boy) ,rare mutation in carrier females cases .
*cause of death mostly paralysis of resp. & cardiac muscles .
* CK level intially very high (100 normal level )
* blood sample & muscle biopsy
> genetic testing for dystrophin mutation > PCR .
*neuromuscular assessment to determine severity & management

Question 2

16y boy 👖+ mild progressive proximal muscle weakness

Dx?

Answer 2

Becker’s muscular dystrophy

Question 3

7y boy 👖+ recurrent chest infections + below 5th percentile + greasy stool ( $ of malabsorption) + DM + meconium ileus (in
Dx?
Risk of their future child having CF ?

Answer 3

CF (cystic fibrosis)
Invest .
* sweat test positive
*molecular genetic testing for CFTR .
* AR so (25% normal ,50% carrier ,25% affected ) . {1: 4 }
Also this means mostly his parents were carriers.

Question 4

*Neonatal period (hypotonia & floppy ) + triangular mouth
* 8 y boy + learning difficulties + behavioural disorders + overeating + DM type 2 + Obstructive sleep apnea .
Dx?

Answer 4

Prader-willi $

Question 5

Hypermobilty + hyperlaxity + blue sclera.

Answer 5

Ehler-Danlos $

Question 6

44y ( female👗> more common ) +recent started rt handed involuntary writing movement (chorea) + memory loss + poor concentration+ +ve FX of similar condition .
Dx?

Answer 6

Huntington’s disease

*AD

Question 7

xy 👖+ MR (IQ 90 )+ behavioural lbs + long limbs + tall + infertility+ hypogonadism + gynecomastia.
Dx ?

Answer 7

Klinefelter’s $ ( XXY )

Question 8

Child with 17 alpha hydroxlase deficiency + her mother is pregnant nw .
What is the risks of her future child having the same pb ?

Answer 8

Dx ; congenital adrenal hypoplasia

* AR {1: 4}

Question 9

32y XX 👗+ cafe au lait spots seen at birth + axillary freckles .
Risk of future child to have the same pb ?

Answer 9

Dx: neurofibromatosis  
* AD {1: 2 }
Type 1 ( more skin form +associated with pheochromcytoma )
Type 2 ( central form with CNS tumors )

Question 10

Hx of polycystic kidney diz + brother died of intracranial insult + not HTN
Cause of her brother death ?

Answer 10

SAH ( subarachnoid hge )

PCK associated with cerebral aneurysm > Rupture > SAH

Question 11

15y XX 👗+ 1ry amenorrhea + short stature + broad chest with widely spaced nipples
Dx?

Answer 11

Dx: Turner $

• Exclude down & fragile x $ as they not presenting with 1ry amenorrhea
• Klinefelter’s $ affect males 😁

Question 12

42y woman 👗(over 35y is considered a high risk pregnency ) +16w pregnant + her 1st child with down $ + she missed her 1st trimester scan
Difintive invest . at this stage ?

Answer 12

Amniocentesis 
* used for diagnosis of 
# NTD (neural tube defect ) .
# chromosomal a normality
# inborn error of metabolism 
*timing 🤔
1st tried (12-14 w but associated with high risk of abortion 😢) 
2nd trib( 15-18 w most recommended 😉) 
3rd tried for karyotyping .