Genetics of Connective Tissue Disorders

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What is the inheritance pattern of Marfan syndrome?

Autosomal dominant
Gene involvement in Marfan syndrome

Mutation in fibrillin gene (FBN1)
What are the symptoms of Marfan syndrome? (6)
- Tall stature
- Flexible joints
- Long limbs
- Scoliosis
- Mitral valve prolapse
- Aortic aneurysm
What is the leading cause of premature death in Marfan syndrome?

Acute aortic dissection
Marfan syndrome is a disorder of…

The fibrous connective tissue
Osteogenesis imperfecta gene involvement

Mutations in COL1A1 or COL1A2 genes, leading to a substitution of G in the GXY motif
Osteogenesis imperfecta mode of inheritance

Autosomal dominant
What are the symptoms of osteogenesis imperfecta?

Weak bones and irregular connective tissue
What are the 5 main types of osteogenesis imperfecta in order of increasing severity?
- Type I: classic non-deforming OI
- Type IV: common variable OI
- Type V: OI with calcification
- Type III: progressively deforming OI
- Type II: perinatally lethal
What is the difference between a quantitative and a qualitative change in type I collagen?
- Quantitative: mutated protein is not incorporated into type I collagen
- Qualitative: mutated protein is incorporated into type I collagen
________________ mutations are associated with a quantitative decrease in type I collagen

Null
________________ mutations are associated with a qualitative change in type I collagen

Dominant negative
What is the most common type of osteogenesis imperfecta?

Type I classic non-deforming
Type I OI is genes involved

COL1A1
What are the symptoms of type I OI?
- Protrusion of eyes
- Discoloration of sclera
- Hearing loss
- Bones fracture easily
- Slight spinal curvature
- Poor muscle tone
____________ osteogenesis imperfecta is the most severe form among children who survive neonatal period

Type III
Type III OI genes involved

COL1A1 or COL1A2
What are the symptoms of type III OI?
- Severe bone fragility
- Multiple fractures at birth
- Deformity of the skeleton
- Kyphoscoliosis
- Bowed limbs
What is the most severe form of osteogenesis imperfecta?

Type II
Type II OI genes involved

COL1A1 or COL1A2
What is epidermolysis bullosa?

Group of genetic conditions that result in blistering of skin and mucous membranes
_________________ is the simplest, most superficial form of epidermolysis bullosa

Epidermolysis bullosa simplex
What is the inheritance pattern of epidermolysis bullosa simplex?

Autosomal dominant
Genes involved in epidermolysis bullosa simplex

KRT5 and KRT14
Symptoms of epidermolysis bullosa simplex

Reduced ability of skin to resist mechanical stress
Tonofilaments are involved in what disease?

Epidermolysis bullosa simplex
What is the inheritance pattern of junctional epidermolysis bullosa?

Autosomal recessive
What are the symptoms of junctional epidermolysis bullosa?
- Abnormalities of GU system
- Blistering in lamina lucida
- Neonatal death
Genes involved in junctional epidermolysis bullosa
- LAMA3
- LAMB3
- LAMC2
- COL17A1
- (Genes encoding laminin 332 and collagen XVII)
Hemidesmosomes are involved in what disease?

Junctional epidermolysis bullosa
Anchoring fibrils (type VII collagen) are involved in what disease?

Dystrophic epidermolysis bullosa
What is the inheritance pattern of dystrophic epidermolysis bullosa?

Autosomal recessive (severe) or dominant
What are the symptoms of dystrophic epidermolysis bullosa?

Abnormalities of GU system
Genes involved in dystrophic epidermolysis bullosa

COL7A1 gene (encodes type VII collagen)
Issues attaching the epidermis to the underlying layers of skin is a characteristic of which disease?

Epidermolysis bullosa
_________________ is the most common hereditary connective tissue disorder
- Ehlers-Danlos syndrome
- What is Ehlers-Danlos syndrome?
- Group of disorders affecting connective tissues
What is the inheritance pattern for classical Ehlers-Danlos syndrome?

Autosomal dominant
Genes involved in classical Ehlers-Danlos syndrome

COL5A1 or COL5A2 (encode type V collagen)
What are the symptoms in classical Ehlers-Danlos syndrome? (5)
- Fragile skin
- Easy bruising
- Poor healing
- Skin elasticity
- Joint dislocations
__________________ is the least severe subtype of Ehlers-Danlos syndrome

Hypermobile Ehlers-Danlos syndrome
__________________ is the most common subtype of Ehlers-Danlos syndrome

Hypermobile Ehlers-Danlos syndrome
What is the inheritance pattern in hypermobile Ehlers-Danlos syndrome?

Autosomal dominant
What are the symptoms of hypermobile Ehlers-Danlos syndrome?
- Joint hypermobility
- Joint dislocations
- Normal skin
- Fatigue
- Pain
What is the inheritance pattern in vascular Ehlers-Danlos syndrome?

Autosomal dominant
Genes involved in vascular Ehlers-Danlos syndrome

COL3A1 (majority) or COL1A1 (minority)
What are the symptoms of vascular Ehlers-Danlos syndrome?
- Thin, translucent skin with visible blood vessels
- Short stature
- Thin hair
- Large eyes
- No ear lobes
What is the protein affected in Ehlers-Danlos syndrome?

Collagen
What is the protein affected in osteogenesis imperfecta?

Collagen
What is the protein affected in epidermolysis bullosa simplex?

Tropofilament (keratin)
What is the protein affected in junctional epidermolysis bullosa?

Laminin 332 and collagen XVII
What is the protein affected in dystrophic epidermolysis bullosa?

Anchoring fibrils (type VII collagen)

Author

stepha998

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Card Set

Genetics of Connective Tissue Disorders

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ATSU

Updated

2018-11-06T05:05:25Z

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