Neurofibromatosis/Tuberous sclerosis

Question 1

What is the aetiology of neurofibromatosis 1

Answer 1

Autosomal dominant with high penetrance
Mutation In NF1 gene, but 50% De Novo mutation

Question 2

What are the risk factors fo neurofibromatosis

Answer 2

MEN2
Pulmonary HTN
Phaeochromocytoma (VHL, NH1, MEN2)
RAS with HTN

Question 3

What are the symptoms and signs of neurofibromatosis

Answer 3

need ≥2 of the following to diagnose:
≥6 café au lait spots, >5mm pre-puberty, >15mm post-puberty
Cutaneous features more prominent after puberty
>1 neurofibroma – firm nodular overgrowth of nerve
Axillary freckles
Optic glioma ± visual impairment
One Lisch nodule – hamartoma of iris (on slit-lamp exam)
Bony lesions from spheroid dysplasia ± eye protrusion
First degree relative with NF1

Question 4

What is the aetiology of tuberous sclerosis

Answer 4

Autosomal dominant
70% de novo mutations
Genetic mutation in TSC1 or 2 genes

Question 5

What are the signs and symptoms of tuberous scerlosis

Answer 5

Cutaneous: Woods lamp (“Ash leaf patch”/amelantoic naevi) | Shagreen patches (rough skin or lumbar spine) | angiofibroma (butterfly facial distribution)

Neurological: infantile spasms | developmental delay | epilepsy | intellectual disability
Nodules develop in brain → subependymal giant cell astrocytoma → non-communicating hydrocephalus

Other: subungual features, dense white areas on retina (local degeneration) | rhabdomyomata of heart | ANGIOMYOLIPOMA

Question 6

What investigations should be done for tuberous sclerosis

Answer 6

CT scan (calcified subependymal nodules and tubers from 2+ years)
MRI (more sensitive and clearly identified other tubers and lesions)