Genetics Flashcards
What are glycogen storage diseases?
A metabolic disorder caused by enzyme deficiencies, affecting glycogen synthesis, glycogenolysis or glycolysis
What is alcaptonuria?
An amino acid degradation disease where phenylalanine and tyrosine degradation is blocked
What is maple syrup urine disease?
Degradation of valine, isoleucine and leucine is blocked
Results in mental and physical retardation and is prevented with an appropriate diet
What is phenylketonuria?
Phenylalanine accumulates in all the body fluids which leads to severe mental retardation if untreated
Therapy - low phenylalanine diet
What are urea cycle disorders?
Accumulation of urea cycle intermediates
Treatment with a low protein diet
What are 2 inherited colon cancer syndromes?
Hereditary non-polyposis colorectal cancer (HNPCC)
Adenomatous polyposis coli syndrome
What is hereditary non-polyposis colorectal cancer?
An autosomal dominant inherited disease
Mutation in the MMR gene
Accounts for 2-7% of colorectal cancer
Patients with HNPCC have an 85% chance of developing colorectal cancer
Early onset - mid-40s but can also be mid 20s
Screening colonoscopy is recommended every 2 years at age 25 and every year at age 40
What is adenomatous polyposis coli syndrome (APC)?
Responsible for 1% of colorectal cancers
2 types - familial adenomatous polyposis (FAP) and Gardner’s syndrome
Patients usually begin developing colonic adenomas during childhood
How common is hereditary haemochromatosis?
Most common genetic disorder in the Caucasian population (1 in 200 people)
How common is a-1-antitrypsin deficiency (A1AT)?
Approximately 1 in 1800 live births
Presents as prolonged obstructive jaundice in an infant
What is Wilson disease?
An autosomal recessive condition found in 1 in 30 000 persons
Characterised by hepatic and neurological manifestations of copper accumulation
