genetics of multi-systemic disorders Flashcards
modes of inheritance
chromosomal: numerical, structural
single gene: autosomal, recesessive, X-linked
multifactorial: polygenic, environment
why multi-system involvement
- several genes with diverse functions: chromosomal (duplications, deletions)
- single gene expressed in different tissues
- single gene tissue-specific expression but tissue integral of many systems
common problems in multi-systemic disease
variable expression between and within families - hard to predict phenotypes
present to wide variety of specialists
FH can be easily missed
NF1 diagnostic criteria 2+ of
optic glioma cafe au lait spots neurofibromas axillary freckling thinning long bone cortex FH NF1 lisch nodules
NF1 further features
learning difficulties dysmorphic features short statures macrocephaly tibial dysplasia epilepsy scoliosis HTN neoplasia
NF1 genetics
autosomal dominant
variable expression
17q tumour suppressor gene
NF1 management
annual review scoliosis tibia learning assessment BP ?selumetinib
tuberous sclerosis classic triad
learning disability
skin lesions
epilepsy
tuberous sclerosis genetics
autosomal dominant
variable expressin
TSC1, TSC2
tuberous sclerosis features
myoclonic seizures LD skin leisons phakoma of eye rhamdomyomas of heart kidney cysts
screening at risk relatives tuberous sclerosis
Cranial MR scan
renal USS
echocardiogram
myotonic dystrophy genetics
autosomal dominant
CTG repeat, worsening severity each generation
myotonic dystrophy features
late onset bilateral cataract weak, stiff muscles myotonia low motivation bowel problems DM
