Genetics -Fahim

Question 1

A female infant has upslanted eyes with epicanthal folds, and a flattened occiput. During your exam, you note developmental delay. What is the most probable mechanism of her disease?
A. Robertson Translocation
B. Mosaicism
C. Meiotic non-disjunction of homologous chromosomes
D. Translocation

Answer 1

C. Meiotic non-disjunction of homologous chromosomes

Question 2

What is Fahim’s crazy mnemonic for Down’s syndrome?

Answer 2

ADVIL DOWN
A=Aneuploidy due to nondisjunction; Alzheimer’s
D=duodenal atresia, double bubble, duodenal web
V=AV canal defect
I=Iris speckles=brushfield spots
L=leukemia risk increased. Laxity (hypotonia); Laxity of the AA joint

Question 3

What is Fahim’s crazy mnemonic for Edward’s disease?

Answer 3

EDWARDS –> some creasy story about going to the movies

Eighteen (trisomy)
Digit overlapping flexion 
W=narroW nose and bifrontal diameter 
Absent intellect 
Rocker-bottom feet 
Diseased heart 
Small lower jaw/short sternum

Question 4

What is Fahim’s crazy mnemonic for Patau syndrome?

Answer 4

"Patau is punched out" --> (Trisomy 13 =Puberty at 13)
Scalp 
Abdomen=omphalocele 
Brain=holoprosencephaly 
Mouth=cleft lip and palate 
Heart=congenital heart disease

Question 5

What is the happy puppy syndrome? What is the genetic deletion? What is the same deletion as this on a paternal gene called?

Answer 5

Angelman syndrome (wide mouth, wide spaced teeth, wide laugh, wide gait (ataxia), wide mandible, absent speech)

15q deletion

Prader-willi=paternal

Question 6

Step 1 Board Review Question: A 14-month-old boy presents with recurrent viral and fungal infections, congenital heart defects, tetany, and anatomic malformations in the neck. The abnormal cells in his spleen would be found in which of the following areas?
A. Periarterial lymphoid sheath
B. Splenic artery
C. Splenic capsule
D. Splenic vein
E. White pulp follicles

Answer 6

A. Periarterial lymphoid sheath

Question 7

One of your favorite patients was just diagnosed with Williams Syndrome. Which chromosome has a deletion?
A. 3
B. 4
C. 5
D. 6
E. 7

Answer 7

7

Question 8

While in on your OB rotation, you help deliver a baby who is over 3500 g. The mom doesn’t have a h/o gestational diabetes. Which genetic disease should you keep on your ddx?

Answer 8

Beckwith-Wiedemann Syndrome:
short arm of the 11th

5 diagnostic features:

• Macroglossia
• Macrosomia
• Midline abdominal wall defects
• Ear creases or pits
• Neonatal hypoglycemia
• Everything is WIDE, except head
• Wilms’ tumor (nephroblastoma) and hepatoblastoma
• Uniparental Disomy

Question 9

A couple presents for an evaluation of male infertiliy. The husband’s height is 6 ft 2 in; his weight is 150 lb. His arms and legs are long in comparison with his torso. Genital exam reveal small, firm testicles in the scrotum bilaterally. What is the most likely etiology of this gonadal abnormality?
A. cryptorchidism
B. Klinefelter’s syndrome
C. panhypopituitarism
D. Turner’s Syndrome

Answer 9

B. Klinefelter’s syndrome (47, XXY)

Question 10

A 16yo girl is brought to you because of an absence of menarche. She has short stature, a webbed neck, and a square chest. PE reveals breast buds and female external genitalia. Her blood pressure is normal in both arms. CT reveals a small uterus and atretic, fatty ovaries. What disease comes to mind?
Which cardiac abnormality is this associated with?

Answer 10

Turners 45 XO

coarctation of the aorta

Question 11

What is the mnemonic for Turner’s syndrome?

Answer 11

“Turn your hand like a CLOWNS”

Cardiac anomalies 
Lymphoedema, low thyroid
Ovaries underdeveloped 
Webbed neck 
Nipples widely spaced 
Short stature, sensorineural hearing loss, Short 4th metacarpal

Question 12

What is crazy’s mnemonic for Fragile X?

Answer 12

FEMALES --> remember a fragile female that like to nag and repeat a lot (trinucleotide repeat) 
FMR1 gene 
Exhibits anticipation 
Macro-orchidism 
Autism 
Long face and large jaw 
Everted  eyes 
Second most common cause of genetic mental retardation (downs=1st)

Question 13

Step 1 Board Review Question: A tall, slim, 13-year-old boy  presents to the ophthalmologist with a sudden change in vision. Examination shows lens subluxation. The patient has always been tall and thin for his age, and a family history reveals that his uncle died from a ruptured aortic aneurysm. On physical examination, the patient is found to have long and slender fingers, ligament laxity, an abnormal ratio of arm length to height, and a diastolic murmur over the aortic area.  Which of the following is most likely deficient in this patient?
A. Dystrophin 
B. Elastase 
C. Fibrillin 
D. LDL cholesterol receptor 
E. Type I collagen

Answer 13

C. Fibrillin

Question 14

What are the important characteristics of Marfan’s syndrome?

Answer 14

• fibrillin
• aortic root dilation
• tall, elongated extremities with joint laxity and chest wall deformities
• UPWARD lens subluxation
• autosomal dominant

Question 15

Case: A family brings a newly adopted 4-year-old son for a routine health supervision visit. Weight and length are 25th percentile; head circumference is at 90th percentile. He is alert and shy. On examination, you count 12 café au lait spots, and he has extensive auxiliary freckling. You also notice lesions on his iris and he seems to be only able to see out of his left eye. What is his diagnosis?

Answer 15

Neurofibromatosis Type 1

Diagnosis requires 2+ of the following:
6+ café au lait macules (must be >5mm in diameter in prepubertal & 1.5cm in pubertal children)
Axillary or inguinal freckling
2+ Lisch nodules (melanocytic hamartomas)
2+ Neurofibromas or one plexiform neurofibroma
Osseous lesion thinning of long bone or sphenoid dysplasia
Optic glioma
First degree relative w/ confirmed NF!