Genetics

Question 1

What are the features of Russell Silver Syndrome?

Answer 1

• Postnatal growth restriction (normal HC)
• Triangular facies with a prominent forehead and pointed chin and clinodactyly
• Males cryptoorchidism, micropenis
• FTT
• Feeding difficulties

Question 2

How do you diagnose Russell Silver Syndrome?

Answer 2

-Clinical (growth restriction, N HC and triangular facies with a prominent forehead and pointed chin) and confirm with methylation analysis, deletion/duplication studies and array for UPD7

Question 3

When should you do cervical spine x-rays in a child with Trisomy 21?

Answer 3

AAP does not recommend routine imaging of cervical spine. You should do neutral c-spine x-rays in a symptomatic child:

• Neck pain, radicular pain, weakness, spasticity or change in tone, gait difficulties, hyperreflexia, change in bowel or bladder function
• Special Olympics may have their own screening requirements
• Counsel on maintaining neutral neck positioning for procedures etc.
• Avoid trampolines w/o direct supervision

Question 4

What is the inheritance pattern of NF1?

Answer 4

Autosomal dominant (50% are inherited from parent and 50% are de novo)

Question 5

What is the diagnostic criteria for NF1?

Answer 5

Diagnostic criteria is 2+ of the following (6 things +FHx):

• 6 hyperpigmented cafe au lait macules (5mm in children, 15mm postpuberty)
• 2+ neurofibromas or 1 plexiform neurofibroma
• Axillary or inguinal freckling (often appears in late childhood)
• Optic glioma (<10 years of age)
• 2+ Lisch nodules (iris hamartomas, <20 yeras of age)
• Tibial pseudoarthrosis or sphenoid dysplasia
• First-degree relative with NF1 (although a sig. percent are de novo mutations)