Neurofibromatosis 1

Page 1

NF1

Life expectancy 8 years lower than general population

Multiple café au lait spots

Axillary freckling

Multiple cutaneous fibromas

Lisch nodules

LD in 50%

Plexiform neurofibromas

Optic nerve gliomas (can lead to blindness)

Malignant peripheral nerve sheath tumours (high mortality

rate but only occur in 1-3%)

Scoliosis

Tibial dysplasia

Vasculopathy

Increased risk of other cancers, including breast cancer

Radiotherapy (previously used to treat optic glioma)

increases cancer risk - MPNST

Diagnosis:

Six or more café au lait macules over 5 mm

in greatest diameter in prepubertal individuals and over 15 mm in greatest

diameter in postpubertal individuals

Two or more neurofibromas of any type or

one plexiform neurofibroma

Freckling in the axillary or inguinal regions

Optic glioma

Two or more Lisch nodules (iris hamartomas)

A distinctive osseous lesion such as sphenoid dysplasia or

tibial pseudarthrosis

A first-degree relative (parent, sib, or offspring)

with NF1 as defined by the above criteria

If a child has more than 6 café au lait spots they should be

strongly suspected as having NF1 (95% chance)

Genetic testing rarely needed

Management:

After diagnosis, the following investigations:

Genetics consultation

Physical examination of skin, skeleton, cardiovascular

system and neurological system

Developmental assessment in children

Neurofibromas can be removed surgically (plexiforms

difficult to remove in this manner)

Pain may indicate peripheral nerve sheath tumour and

warrants investigation using MRI >> complete surgical excision

Chemotherapy for progressive optic nerve gliomas in children

Surveillance:

Annual physical examination

Annual ophthalmic investigation

Regular Developmental assessment of children

Blood pressure monitoring

Early breast screening to be considered

Inheritance:

Autosomal Dominant

1 in 2,500 live births

Extreme clinical variability within families (need second

hit to manifest phenotype)

50% of cases are de novo

Mutation in TS gene Neurofibromin

Whole gene deletion mutation – more severe phenotype

Clinical features

diagnosis

treatment & surveillance

inheritance