NEUROCUTANEOUS SYNDROMES

Question 1

What is the inheritance pattern of neurofibromatosis type 1?

Answer 1

Autosomal dominant

Question 2

What is the incidence of live births affected by neurofibromatosis type 1?

Answer 2

1 in 4000

Question 3

What proportion of individuals affected by neurofibromatosis type 1 are the result of a new mutation?

Answer 3

50%

Question 4

What chromosome is the mutation for neurofibromatosis type 1 found on?

Answer 4

Chromosome 17

Question 5

What are the clinical features of neurofibromatosis type 1?

Answer 5

Cafe au lait patches - must be at least 6 for diagnosis

Lisch nodules (pigmented hamartomas on the eye)

Optic gliomas

Neurofibromas on the peripheral nerves (may be palpable)

Tumours of the CNS (benign or malignant)

Epilepsy

Learning difficulties - ADHD, speech and language, Asperger’s

Scoliosis

Pheochromocytoma

Question 6

How do we manage children with neurofibromatosis type 1?

Answer 6

Monitored each year for growths. Surgical removal of tumors is an option, however the risks involved should be assessed first.

Question 7

What is the characteristic features of neurofibromatosis type 2, which is rarely a feature of neurofibromatosis type 1?

Answer 7

Bilateral acoustic neuroma (tumours in the region of the VIIIth cranial nerve)

Question 8

What is the inheritance pattern of tuberous sclerosis?

Answer 8

Autosomal dominant, although up to 75% of cases represent new mutations.

Question 9

What are the classic clinical features of tuberous sclerosis?

Answer 9

Seizures

Mental retardation

Facial angofibromas, also called adenoma sebaceum (often in a butterfly distribution across the face)

Hypopigmented macules called ash leaf spots

Shagreen patches (roughened patches of skin over spine)

Widespread tumours distributed across many organs

Question 10

Which organs are classically affected by benign tumours and cysts in tuberous sclerosis?

Answer 10

Skin

Brain and eyes

Kidney

Heart

Lungs

Question 11

What is the best way to examine ash leaf spots (the hypopigmented macules seen in tuberous sclerosis)?

Answer 11

Best seen with a Wood’s light

Question 12

What are the clinical features of Sturge-Weber?

Answer 12

Unilateral facial naevus (port wine stain) in distribution of trigeminal nerve

Seizures - caused by angiomas involving the leptomeningeal vessels in the brain

Haemangiomas of the spinal cord

Glaucoma

Question 13

What is classically seen on brain imaging of a person with Sturge-Weber syndrome?

Answer 13

Unilateral intracranial calcification with a double contour like railway line and cortical atrophy