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Flashcards in Genetics - Dysmorphology Deck (27)

 A 40 year old male had a lesion on his abdomen removed. Pathology identified it as a Neurofibroma. On physical exam the patient has 10 café au lait spots and axillary freckling.
 Which is the most likely diagnosis

A. Tuberous Sclerosis
B. Noonan syndrome
C. Neurofibromatosis
D. Normal Variant
E. Klinefelter Syndrome

C. Neurofibromatosis


What is the inheritance of neurofibromatosis?

Autosomal Dominant


What are Lisch nodules?

Iris hamartomas that are associated with neurofibromatosis


What bone defect can be seen in neurofibromatosis?

Osseous defect of the fibula - can be present in infancy


A 22 year old female has a father who was recently diagnosed with Marfan syndrome. He has a mutation of the FBN1 gene. She was found to have the same change to the FBN1 gene. Which of the following is recommended.

A. Renal Ultrasound
B. Head CT
C. Audiology exam
D. Echocardiogram
E. Pulmonary function test

D. Echocardiogram


What heart abnormality can be seen in patients with Marfan syndrome?

Mitral Valve Prolapse


What is the main cause of morbidity in Marfan syndrome patients?

Aortic Dissection


What is the inheritance of Marfan syndrome?

Autosomal Dominant


What is the risk for Marfan syndrome patients to pass the disease onto their children?



How does losartan act in Marfan syndrome in a beneficial manner?

When fibrillin is abnormal there is up regulation of the angiotensin receptor (AT1) which increases SMAD 2 which increases TBFB, this results in aortic root dilatation.

Losrtan blocks the AT1 receptor.


A 3 year old male was diagnosed with autism and cognitive delays. He has a long face, large ears and hypermobile joints. The most likely diagnosis is:

 A. Fragile X syndrome
 B. Down syndrome
 C. 22q11 deletion syndrome
 D. Phenylkeptonuria
 E. Homocystinuria

 A. Fragile X syndrome


What is the most common cause of inherited mental retardation?

Fragile X Syndrome


What are some features of Fragile X syndrome?

- Prominent or large ears
- Long face
- Prognathism
- Hyper-extensible joints
- Macro-orchidism


Is karyotyping done for Fragile X syndrome?



What is the characteristic nucleotide repeat in Fragile X?

CGG repeats - over 200 repeats that are found leading to methylation and causing the gene to be non-functional


A 5 year old male is having increasing frequency of toe walking. He has difficulty going up stairs. The creatinine kinase was measured at 22,000 (nl 0- 50). Which is the most likely diagnosis?

A. Down syndrome
B. Myotonic Dystrophy
C. Duchenne Muscular Dystrophy
D. Fragile X syndrome
E. Pompe disease

C. Duchenne Muscular Dystrophy


What is the inheritance of Duchenne Muscular Dystrophy?

X-linked Recessive


What is most often the cause of death in Duchenne Muscular Dystrophy?

Heart failure second to dilated cardiomyopathy


What is the mutation in Duchenne Muscular Dystrophy?

Dystrophin - no dystrophin is produced


A 2 month old female has macroglossia, hemihypertrophy and glabellar hemangioma. Which of the following is the patient at greatest risk for:

A. Fracture
B. Anemia
C. Colon cancer
D. Aortic root dilatation
E. Wilms tumor

E. Wilms tumor


What are the features of Beckwith-Wiedeman syndrome?

- Increased birth weight
- Hypoglycemia (neonatal)
- Hypocalcemia
- Anterior ear creases


What do infants born by IVF have increased risk for?

Beckwith-Wiedemann syndrome


What is the mutation in Beckwith-Wiedemann syndrome?

Caused by a duplication of the insulin growth factor
receptor (11p)


What tumors are patients with Beckwith-Wiedemann at increased risk for?

- Wilms Tumor
- Hepatoblastoma


A 3 year old male has gross motor delays. He was diagnosed with Fetal Alcohol syndrome. Which of the following is the most common physical feature:

 A. Macrocephaly
 B. Short stature
 C. Congenital heart defect
 D. Short palbebral fissure
 E. Polydactyly

B. Short stature
D. Short palbebral fissure

Both are correct.


What disease are these features associated with:
- Microcephaly
- Low birth weight
- Failure to thrive
- Long smooth philtrum
- Thin upper lip
- Hearing loss
- Congenital heart defects

Fetal Alcohol Syndrome


What is the cause of fetal alcohol syndrome?

Prenatal alcohol exposure

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