18 Questions
Which gene/defect is associated with Huntington Disease?
Huntingtin (HD) - CAG repeat
What type of inheritance pattern is seen in Glucose 6-phosphate dehydrogenase deficiency?
X-linked recessive
Which clinical feature is characteristic of Marfan Syndrome?
Excessive elasticity of the skin and aortic dilatation
What type of genetic disorder is Cri du Chat Syndrome?
Chromosomal (Autosomal)
What is the main cause of anemia in Glucose 6-phosphate dehydrogenase deficiency?
Increased hemolysis triggered by certain drugs and foods
Which symptom is not typically seen in Huntington Disease?
Increased hemolysis
What is the gene/defect associated with Cystic Fibrosis?
Cystic fibrosis transmembrane regulator (CFTR)
How is Cystic Fibrosis inherited?
Autosomal recessive
What are the clinical features of Cystic Fibrosis?
Impaired chloride ion channel function
Which type of genetic disorder is Cystic Fibrosis among Caucasians in North America?
Autosomal recessive
What impact does Cystic Fibrosis have on chloride ion channels?
It impairs their function
Why do normal parents have the potential to have an affected child with Cystic Fibrosis?
Due to being carriers of a recessive mutated CFTR gene
What is the inheritance pattern of the disease associated with Myoclonic Epilepsy?
Maternal transmission
Which gene/defect is associated with Osteogenesis Imperfecta?
Genes encoding the α1 or α2 chains of type I collagen
What is a common clinical feature of individuals with the disease linked to Hypercholesterolemia gene/defect?
Impaired uptake of LDL
In individuals with Cystic Fibrosis, which system is primarily affected?
Respiratory system
What type of mutation can result in a milder form of Osteogenesis Imperfecta?
Null mutation
What is the characteristic clinical feature of individuals with the disease related to Myoclonic Epilepsy?
Ataxia
Study Notes
Mitochondrial Dysfunction
- High levels of mutations cause mitochondrial dysfunction, affecting ATP levels and other cellular processes.
- Mitochondrial myopathy is a disorder that causes muscle weakness, fatigue, and difficulty with motor skills due to impaired mitochondrial function in muscles.
Achondroplasia
- Caused by a gain-of-function mutation in the fibroblast growth factor receptor 3 (FGFR3) gene.
- Autosomal dominant inheritance.
- Clinical features: short limbs relative to trunk, prominent forehead, low nasal root, and redundant skin folds on arms and legs.
Cystic Fibrosis
- Caused by impaired chloride ion channel function in the cystic fibrosis transmembrane regulator (CFTR) gene.
- Autosomal recessive inheritance.
- Clinical features: similar to achondroplasia.
Duchenne Muscular Dystrophy
- Caused by deletions in the dystrophin (DMD) gene.
- X-linked recessive inheritance.
- Clinical features: gradual degeneration of skeletal muscle, impaired heart and respiratory musculature.
Gaucher's Disease
- Caused by deficiency of β-glucosidase.
- Autosomal recessive inheritance.
- Clinical features: lysosomal storage disease characterized by splenomegaly, hepatomegaly, and bone marrow infiltration. Neurological symptoms are rare.
Glucose 6-Phosphate Dehydrogenase Deficiency
- Caused by deficiency of glucose 6-phosphate dehydrogenase.
- X-linked recessive inheritance.
- Clinical features: anemia induced by oxidizing drugs, sulfonamide antibiotics, sulfones, and certain foods.
Huntington's Disease
- Caused by CAG repeat in the Huntingtin (HD) gene.
- Autosomal dominant inheritance with anticipation.
- Clinical features: progressive motor, cognitive, and psychiatric abnormalities, including chorea (non-repetitive involuntary jerks) in 90% of patients.
Marfan Syndrome
- Caused by mutations in the fibrillin-1 gene (FBN1).
- Autosomal dominant inheritance with a dominant negative effect.
- Clinical features: abnormalities of the skeleton, heart, pulmonary system, skin, and joints.
Cri du Chat Syndrome
- Caused by deletion of the long arm of chromosome 5 (5p-).
- Autosomal inheritance.
- Clinical features: severe mental retardation, microcephaly, "cat-like cry," cirrhosis, cardiomyopathy, diabetes, skin pigmentation, and arthritis.
Hypercholesterolemia
- Caused by mutations in the LDL receptor gene.
- Autosomal dominant inheritance with haploinsufficiency.
- Clinical features: impaired uptake of LDL, elevated levels of LDL cholesterol, cardiovascular disease, and stroke.
Myoclonic Epilepsy with Ragged Red Fibers (MERRF)
- Caused by mutations in the mitochondrial DNA tRNAlys gene.
- Maternal transmission with heteroplasty.
- Clinical features: myopathy, dementia, myoclonic seizures, ataxia, and deafness, with age of onset varying depending on the fraction of mutant mitochondrial DNA inherited.
Osteogenesis Imperfecta
- Caused by mutations in the genes encoding the α1 or α2 chains of type I collagen.
- Autosomal dominant inheritance with null mutations resulting in haploinsufficiency and missense mutations producing a dominant negative effect.
- Clinical features: deformed, undermineralized bones prone to frequent fracture.
Explore common genetic disorders like Achondroplasia and learn about the consequences of mutations causing mitochondrial dysfunction. Understand how mitochondrial myopathy affects muscle function due to impaired mitochondria. Delve into the impacts on ATP levels and cellular processes.
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