Week 108 Flashcards
(46 cards)
Huntington disease
Autosomal dominant
Neurodegenerative; causing lack of coordination, unsteady gain, problems with mood or cognition, chorea, early death (life expect around 15y after diagnosis)
Accumulation of mutant HUNTINGTIN protein
Marfan syndrome
Autosomal dominant
Connective tissue disorder; unusually tall with long limbs and long thin fingers and toes; associated with heart valve and aorta defects leading to death.
Familial hypercholestrolaemia
Autosomal dominant
High cholestrol levels, specifically LDL, leading to early CVD.
Spinocerebellar ataxia
Autosomal dominant
Progressive degenrative disease causing slowly progressive incoordination of gain and associated poor coordination of hands, speech and eye movements.
Familial adenomatous polyposis
Autosomal dominant
Hundreds or thousands of small polyps grow in the large bowel which will almost definitely develop into cancer. Needs regular colonoscopies and possible bowel resection.
Hereditary breast and ovarian cancer
Autosomal dominant
HBOC syndrome is associated with young diagnoses of breast or ovarian cancer within the family. It is caused by BRCA1 and BRCA2 gene mutations.
Myotonic dystrophy
Autosomal dominant
Muscular dystrophy (progressive muscle wasting and weakness) that starts in adulthood. Prolonged muscle contractions (myotonia) and not being able to relax certain muscles after use e.g. difficulty releasing grip.
Long QT syndrome
Autosomal dominant
Delayed repolarisation of the heart increases risk of epiodes of TdP and episodes may lead to palpitations, fainting and sudden death due to VF. Implantable ICD.
Cystic fibrosis
Autosomal recessive
Affects mostly lungs but also pancrease, liver, kidneys and intestine. Causes difficulty breathing and coughing up mucus resulting in frequent lung infections. Also sinus infections, poor growth, fatty stool, clubbing, infertility. Mutations in CFTR.
Phenylketonuria
Autosomal recessive
Impaired metabolism of amino acid phenylalanine due to absence of phenylalanine hydroxylase (PAH). Protein rich foods or aspartame sweetener can poison sufferers. Phenylalanine build up affects brain development and function, and can lad to intellectual disability, seizures and other severe problems.
Beta thallasemia
Autosomal recessive
Blood disorder that reduces haemoglobin production, leading to anaemia, hypoxaemia, weakness, fatigue, pallor, increased risk of clots and more serious complications. Children develop life threatening anaemia, often don’t gain weight and may develop jaundice.
Sickle cell anaemia
Autosomal recessive
Abnormality in haemoglobin leads to RBCs assuming abnormal, rigid, sickle shape under certain circumstances. Associated with severe infections, attacks of severe pain (sickle cell crisis), stroke, and increased risk of death,
Tay Sachs disease
Autosomal recessive
Progressive destruction of neurons in the brain and spinal cord. Becomes apparently in infancy (around 6 months), and infants lose motor skills such as turning over, sitting and crawling. They also have an exaggerated startle reaction to loud noises. They go on to experience seizures, vision and hearing loss, disability and paralysis. Usually children die in early childhood.
Spinal muscular atrophy
Autosomal recessive
LOF of neuronal cells in anterior horn of spinal cord leading to system-wide muscle wasting. Often affects proximal muscles and lung muscles first, leading to areflexia, muscle weakness and poor muscle tone, limpness etc.
Duchenne muscular dystrophy
X-linked recessive
Muscle degeneration and premature death due to mutation in dystrophin gene. Symptoms appear around 2y: progressive proximal muscle weakness of the legs and pelvis with loss of muscle mass, which spreads to arms, next and other areas.
Elevated CK levels.
Haemophilia A
X-linked recessive
Deficiency in clotting factor VIII causes increased bleeding. Internal or external bleeding episodes (“bleeds”) e.g. haematomas, prolonged bleeding.
RG colour blindness
X-linked recessive
Difficulty discriminating between red and green hues due to absence or mutation of red or green retinal photoreceptors.
MYH associated polyposis
Autosomal recessive
Development of multiple adenomatous colon polyps with increased risk of colorectal cancer.
Genomic imprinting
One gene copy is inherited form mother and one from father, and both copies are usually active. In imprinting, only one is expressed and the other is “imprinted”. If a faulty gene is imprinted this will not cause problems but if a healthy gene is imprinted and the remaining copy is faulty, this can cause disease.
Uniparental disomy
Person receives two copies of a chromosome from one parent and no copies from the other parent.
Beckwith-Wiedemann syndrome
Autosomal dominant
Paternal UPD of chromosome 11 means that offspring is missing some features of the gene that are only active on the maternal copy of the gene.
Overgrowth syndrome: affected infants are larger than normal (macrosomia) and taller than peers. By adulthood they are not unusually tall. Assymetric appearance (hemihyperplasmia). Increased risk of several types of cancers.
Prader-Willi syndrome
autosomal dominant
Maternal UPD of chromosome 15 means that offspring is lacking the genes within chromosome 15 that are only active on the male copy of the gene.
Neonatal hypotonia, feeding difficulties and poor growth. Developmental delay, LD, insatiable appetite and obesity.
Angelman syndrome
AUTOSOMAL DOMINANT
Paternal UPD of chromosome 15.
Affects nervous system: delayed development, intellectual disability, speech imparment, ataxia, recurrent seizures, small head size, happy excitable demeanor with frequent smiling, laughter and hand flapping movements, hyperactivity, short attention span, fascination with water.
Mosaicism
Two or more DIFFERENT genetic or chromosomal cell lines within a single individual or tissue (somatic = not germ line cell; germ line = germ line cells).
