Genetic disorders Flashcards
Which gene is mutated in type 1 neurofibromatosis (NF1) aka von Recklinghausen’s disease and what type of mutation is this?
Autosomal dominant mutation in neurofibromin gene (tumour suppressor)
What are the cutaneous features of NF1?
1) Cafe-au-lait spots - 6 macules >5mm (of >15mm if post-pubertal)
2) Axillary/inguinal freckling
3) Neurofibromas
What are cafe-au-lait spots?
Oval shaped, coffee-coloured patches, grow throughout life
Can be benign
What are neurofibromas?
Small, nodular tumours in the skin - often formed during puberty
What are the non-cutaneous associations of NF1?
1) Lisch nodules on the iris
2) Optic glioma
3) Scoliosis and malformation of bones
4) Learning difficulties
5) Hypertension
6) GI bleeding/obstruction (due to tumours in the bowel)
7) Epilepsy (due to tumours in the brain)
What are Lisch nodules?
Hamartomas on the iris - appear as brown patches/mounds, usually seen by age 6
What feature can be present in both NF1 and NF2?
Cafe-au-lait spots
What is the triad of symptoms in type 2 neurofibromatosis?
Sensorineural hearing loss, tinnitus, vertigo
What two tumours does NF2 result in?
Meningiomas, bilateral vestibular schwannomas aka acoustic neuromas
What is Von Hippel-Lindau (vHL) syndrome?
Inherited cancer syndrome
Which tumours does vHL syndrome predispose to?
1) Cerebellar and retinal haemangioblastomas
2) Phaeochromocytomas
3) Renal cancers
What type of brain tumours does NF1 predispose to?
Gliomas - usually cerebral (optic)
Which type of tumour is classically seen in Beckwith-Wiedemann syndrome?
Wilm’s tumours aka nephroblastomas
Which two conditions are renal cysts associated with?
1) vHL syndrome
2) Tuberous sclerosis
