NF-1

Question 1

What is the prevalence of NF-1?

Answer 1

1 in 3500

Question 2

What is the diagnostic criteria for NF1?

Answer 2

Two or more of the following seven features:

1. Six or more cafe-au-lait spots >5mm in longest diameter in prepubertal patients and >15mm in longest diameter in postpubertal patients
2. > 2 neurofibromas of any type or 1 plexiform neurofibromas
3. Freckling in the axillary or inguinal regions
4. Optic glioma (optic pathway glioma)
5. Two or more Lisch nodules (iris hamartomas)
6. A distinctive osseus lesion, such as sphenoid wing dysplasia or cortical thinning of the cortex of long bones, with or without pseudoarthrosis
7. A first-degree relative with NF-1

Question 3

What percentage of cases are non-familial?

Answer 3

50%

Question 4

What are the complications of NF-1?

Answer 4

1. Peripheral nerve sheath tumors 5-10%
2. Other malignancies: pheochromocytoma, rhabdomyosarcoma, leukemia, brain tumors other than optic gliomas
3. Short stature ~1/3
4. Neurofibromas in GI tract –> bleeding, obstruction
5. Seizures 6-7%
6. Non-ossifying fibromas of the long bones and esp. the distal femur and proximal tibia can result in fracture
7. Hypertension 4%
   - renal artery stenosis, aortic stenosis, pheochromocytoma
8. MR 4-8%
9. Specific learning disabilities 40-60%

Question 5

What is the inheritance for NF-1?

Answer 5

Autosomal dominant

Question 6

What are the recommendations regarding ongoing assessment and periodic review for NF-1?

Answer 6

1. Evaluate child or new neurofibromas and progression of lesions. Examine the skin carefully for signs of plexiform neurofibromas that may impinge on or infiltrate underlying structures
2. BP q1y
3. Ophtho evaluation q1y
4. Evaluate for skeletal changes. Look for sco-
   liosis, vertebral angulation, and limb abnormalities, esp. tibial dysplasia.
5. Consider screening X-ray knees in adolescence
6. Monitor development and learning