genetic conditions Flashcards
what does autosomal dominant mean
the disease is seen in all generations with a 50% risk of an affected child if one parent is affected
what does de novo mutation mean and when does it occur
this is a new, autosomal dominant mutation, neither parent will have it.
this mutation will occur in gametogenesis
what does autosomal recessive mean
these diseases often only affect one generation with a 25% risk of an affected child if BOTH parents are carrier
what is haploinsufficiency mutation
only one working copy of the gene
what is a dominant negative mutation
expression of an abnormal protein which interferes with the normal protein
what is a gain of function mutation
a mutant protein gains a new function which affects all cell processes
what is a complete loss of protein mutation
this is autosomal recessive, 2 fault copies of a gene will produce NO protein
what is tuberous sclerosis
common genetic disease which presents with benign tumours affecting most body systems
what type of mutation causes tuberous sclerosis, where does it occur
autosomal dominant but de novo are also common.
mutation occurs or chromosome 9 or 16
the production of what is affected in tuberous sclerosis
tuberin and hamartin
what are the symptoms of tuberous sclerosis
infantile seizure due to cortical tubers and/or calcification of fall cerebri epilepsy ash-leaf macule tumours enamel pitting shagreen patches
what tumours are found in tuberous sclerosis
can affect any body site
what is the treatment of tuberous sclerosis
MTOR inhibitor may help
what is epidermolysis bullosa (EB)
group of genetic skin fragility conditions
what causes epidermolysis bullosa
faults in genes encoding for type 1 and 2 keratins
what are the 3 types of epidermolysis bullosa, what do they affect
simplex = affect the epidermis junctional = affect the junction dystrophic = affects the dermis
what are the symptoms of epidermolysis bullosa
widespread blistering
skin loss
what is neurofibromatosis type 1
multisystem genetic disease
what are the symptoms of neurofibromatosis type 1
cafe-au lait macules learning difficulties neurofibromas axillary or inguinal freckling optic glioma distinct bony lesion plexiform neuroma 2 or more lisch nodules
what is a cafe-au lait macules
coffee coloured flat marks. these occur from birth.
> 5 suggests a genetic disease
what are lisch nodules
dome-shaped gelatinous masses developing on the surface of the iris
what is the treatment for neurofibromatosis type 1
MEK inhibitors
