Genetic and Metabolic Medicine Flashcards
Single copy of a set of chromosome
Haploid
Three copies of a set of chromosome
Triploid
Three copies of a single chromosome within a whole cell
Trisomy
Define lyonisation
One of the two X chromosomes in every cell in a female is randomly inactivated early in embryonic development. - forms a Barr body
Characteristics of X-linked dominant conditions
both sexes affected equally, often lethality in males and females less affected
Explain trinucleotide repeat disorders with examples
Increasing numbers of repeats (show anticipation) eg) Myotonic dystrophy, Fragile X, Friedrichs Ataxia
What is MELAS?
Mitochondrial Encephalopathy, Lactic Acidosis and stroke like episodes = mitochondrial inheritance
What is MERRF?
Myoclonic epilepsy with Raggad Red Fibres = mitochondrial inheritance
Tissues usually affected by mitochondrial disorders?
All tissues requiring a lot of energy (Brain, eyes, ears, kidneys)
What is genomic imprinting? + Disorders
Epigenetic phenomenon leading to the exclusive expression of specific genes from only one parent. Disease = uniparental disomy (maternal) - Ch 15 Prader-Willi (paternal) - Ch 15 Angelmans
Genetic syndromes associated with peripheral pulmonary stenosis? (x 2)
Alagile syndrome, Williams syndrome
Genetic syndrome associated with Tetralogy of Fallot? (+ characteristics x 7)
Velocardiofacial Syndrome ~ DiGeorge Sx - 22q11 deletion - Tetralogy of Fallot - Cleft palate - Long face - Bulbous nose, abnormal ears - Short palpebral fissures - learning difficulty
Genetic Syndrome associated with pulmonary stenosis? (+ other characteritstics
Noonan Syndrome
- broad webbed neck
- wide set eyes
- ptosis + epicanthic folds
- Micrognathia
What is propionic acidaemia?
Rare metabolic disorder, affects all tissues
Increased risk of metabolic stroke (in basal ganglia) due to toxic metabolites due to deficiency in enzyme importat for protein breakdown
Seizures/encephalopathy, hypotonia, cardiomyopathy, pancreatitis, vision/hearing loss