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Dr. Anand Saggar

Dr. Anand Saggar - MBBS, CCST, FRCP

Medical Genetic Specialist

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07970 886663

Neurofibromatosis

There are two types of Neurofibromatosis:

Neurofibromatosis type 1

The neurofibromatoses can be distinguished according to type and distribution of hamartomatous lesions. Neurofibromatosis type 1 (NF1) is a common and well known disorder first described by von Recklinghausen in 1849.

Epidemiology

  • Incidence: 1/2500-1/4000
  • Male= Female
  • There is considerable phenotypic variability between members of the same family.

Clinical presentation

Patients with NF1 usually present in childhood with café-au-lait patches or in adulthood with neurofibromas.

Physical Signs

NF1 Diagnostic Criteria [ ]=% of individuals with features

Patients must have 2 or more of the following:

  • Café-au-lait patches 6 or more 5mm prepubertal, >15mm in an adult) [>99%]
  • Axillary or inguinal freckling [85%]
  • Neurofibromas (2 or more cutaneous/ subcutaneous) [>99%]
  • Plexiform neurofibromas (1 or more) [30-50%]
  • Lisch nodules (benign iris hamartomas see on slit lamp) (2 or more) [95%]
  • Optic pathway glioma [15% total, 5% symptomatic]
  • Bony dysplasia (Sphenoid wing/ long bone or pseudarthrosis) [2%]
  • First degree relative with NF1

Complications

  • Mild cognitive impairment [30-60%]
  • Scoliosis [11%]
  • Malignant peripheral nerve sheath tumours [8-13% lifetime risk]
  • Cerebral gliomas [2%]
  • Raised blood pressure may be due to benign essential hyper-tension, renal artery stenosis or phaeochromocytoma [2%]

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Neurofibromatosis type 2 (NF2)

Neurofibromatosis type 2 (NF2) is a much rarer condition and characterised by the formation of VIIIth cranial nerve vestibular schwannomas.

Epidemiology

  • Incidence: 1/40 000-1/100 000

Clinical presentation

  • Typically bilateral vestibular schwannomas, deafness and tinnitus

Physical signs

  • Neurological features secondary to CNS tumour
  • Deafness
  • Cataracts (juvenile)
  • CALS: 4% of patients have >3, 0% of patients have >6
  • In contrast to NF1, plexiform neurofibromas, axillary freckling and lisch nodules are rare

Complications

  • CNS tumours and surgical sequelae

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