Session 17-Genetics In Medicine Flashcards
What are the symptoms of sickle cell anaemia (SCA)? (3)
Anaemia
Fever
Severe pain
Which single DNA mutation causes SCA?
A to T in the beta-globin gene
How does the single DNA mutation cause a change in the beta-globin protein?
Position 6 in the AA chain from Glu to Val
True or false: only one copy of beta-globin needs to be mutated to cause SCA
FALSE-both have to because it is an autosomal recessive disorder
True or false: individuals who are heterozygous for SCA (sickle cell trait) are resistant to malaria
TRUE
What is epigenetics?
Complex web of gene regulation
True or false: foetal gamma globin is turned off after birth and adult beta globin is turned on
TRUE
Can gamma globin be kept switched on?
Yes, it has no impact on health but would prevent SCA
Which protein binds to DNA and switches off the gamma globin gene?
Protein BCL11A (repressor)
What does HSPC stand for and what can it be used in?
Haemopoietic stem and progenitor cells
Used in gene editing therapy for SCA
What is Huntington’s disease (HD)?
Inherited neurodegenerative disease
What are the symptoms of HD? (4)
Seizures
Abnormal gait
Personality change
Dementia
True or false: the mutation causing HD is a short tandem repeat (STR) of CGA
FALSE - it is a STR of CAG
True or false: HD is autosomal recessive
FALSE - autosomal dominant
What is the age of onset of HD?
40-50
True or false: from generation to generation, age of onset of HD becomes earlier and symptoms become more severe
TRUE
How is age of onset of HD affected by CAG repeat length?
Negative correlation - as CAG repeat length increases, age of onset decreases but still lots of variation
What influences age of onset of HD?
Multifactorial - CAG repeat length as well as other genetic factors (one on chromosome 8 and two on chromosome 15)
What causes developmental disorders?
Environment (infection, maternal alcohol etc)
New mutation in gene
True or false: developmental disorders can be found by sequencing the exome (exons of genome)
TRUE
