Mod 5 Exam 2 Flashcards
Silent mutation
A type of substitution, still codes for the same amino acid
Missense mutation
A type of substitution, codes for a different amino acid
Nonsense mutation
A type of substitution, codes for a stop codon - protein truncated
Deletion mutation
Remove one or more nucleotides from DNA - alters the reading frame
X-linked dominant
Sex linked disorder caused by dominant allele on the X chromosome. You only need one allele present to cause disorder
Huntington’s Disease - Type and cause of disorder
Autosomal dominant.
CAG trinucleotide repeat of the HuntingTIN (HTT) gene on Chromosome 4, leads to formation of mutant HTT protein. Affects the Basal ganglia (medium spiny neurons of striatum). GABAgernic neurons are associated with voluntary movement; these are effected. Mutant HTT results in neuronal dysfunction and death
Huntington’s S/ S
On set 30-50 yo.
Cognitive - impaired emotional and executive function
Psychiatric - apathy, anxiety, depression
Chorea - jerky, involuntary movements - esp in hips, shoulders and face
Marfan’s syndrome S/ S
Disorder of connective tissue organization. Long, thin bones with chronic joint laxity. Eye lens dislocation, valve disease, aortic dilation/ dissection. Can have normal life span if symptoms are managed.
Polycystic Kidney Disease - type and cause
Autosomal dominant. Issue with Polycystin genes, which code for polycystin found in cilia of kidney cells. Normally helps to DEC Ca ion levels but mutated genes INC Ca ions levels - the epithelium forms cysts.
Polycystic Kidney Disease - S/ S
Hypertension, headache, flank/ back pain, blood in urine, frequent urination
Charcoat-Marie-Tooth Disease - Type and cause
Autosomal dominant. CMT 1 - myelin protein mutation. CMT2 - mutation of axonal components (less severe).
Charcoat-Marie-Tooth Disease - S/ S
Progressive muscle wasting and loss of touch sensation. Motor impairment begins in lower limbs - foot drop, hammer toe, stork legs. Pain in CNS, muscle cramps, neurogenic pain.
Cystic fibrosis - type and cause
Autosomal recessive. Deletion of 3 nucleotides in the CFTR gene, means you lose phenylalanine. Normally CFTR is a trans membrane Cl channel. Mutated CFTR doesn’t allow Cl out of the cell, this keeps water in the cells - produces thick secretions. Inc salt on skin bc Na can’t get into cell.
Cycstic fibrosis - S/ S
Lung infections, pneumonia, pulmonary fibrosis. Impaired pancreatic exocrine secretion bc the duct gets clogged.
Red-Green colour blindness
X linked recessive. Defect in colour sensing cones (photoreceptors) of retina.
