0Reference: Text book of MD vasudevan
| Disorders | Causes | Defects |
| Osteogenesis Imperfecta (brittle bone disease) | Type I collagen defective Due to mutation in genes COL1A1and COL1A2 coding for pro α1 and pro α2 chains | Bone deformity Blue sclera Dental abnormalities Hearing loss positive family history is seen |
| Ehler - Danlos syndrome | Mutations in amino acid sequences of Collagen types I, III or V | Hyper mobile joints are seen. Prone for Joint dislocations. Hyper elastic skin. Injury to skin leads to typical cigarette paper scars formation. Abnormal collagen synthesis leads to fragile blood vessel formation which are prone to rupture (potentially lethal). Easy bruising is seen. |
| Scurvy | Vitamin C deficiency. | • Loose gums, • Gum bleeding, • Joint space bleeding, • Poor wound healing. |
| Menke disease | Due to mutations in “ATP 7A gene”
| Brittle thin sparse, coarse hair. Deterioration of Nervous system. |
| Alport’s syndrome | Defect in the formation of type IV collagen | Hematuria, Sensorineural hearing loss and ocular abnormalities. |
| Epidermolysis Bullosa | Alteration in the structure of type VII collagen. | Exhibit skin breaks and blisters formation even for minor trauma |
| Williams Syndrome | Impairment in elastin synthesis. Deletion in elastin gene located on Chromosome 7. | Defects in connective tissue and CNS are seen. Supra valvular aortic stenosis is often found in this condition. |
| Marfans syndrome | Due to defect in fibrillin. Autosomal dominant. | Ectopia Lentis Arachnodactyly hyper extensibility of joints. Aortic aneurysm
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