Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
22 Cards in this Set
- Front
- Back
|
3 types of connective tissues and which one is the most common?
|
Collagenous, elastic, and reticular. Collagenous is most common.
|
|
|
What type of collagen is defective in Osteogenesis Imperfecta?
|
Type 1 collagen
|
|
|
Type 1 OI (cause and disease)
|
Autosomal Dominant. Null allele for alpha 1 or 2 genes. Leads to only half of usual protein production.
Frequent fractures, normal height, little deformity, sclera are blue, 50% have hearing loss. |
|
|
Type 2 OI (cause and disease)
|
Autosomal dominant (rarely recessive). Point mutation in either alpha 1 or 2 allele. Mutant protein is produced. 1:3 ratio of normal to mutant collagen for alpha 1 mutation, 1:1 for alpha 2.
Perinatal lethal form, multiple fractures at birth, poor mineralization of bones. |
|
|
Type 3 OI (cause and disease)
|
Autosomal dominant, not commonly recessive.Point mutation in either alpha 1 or 2 allele. Mutant protein is produced. 1:3 ratio of normal to mutant collagen for alpha 1 mutation, 1:1 for alpha 2.
Progressively deforming form, short stature, hearing loss common. |
|
|
Type 4 OI (cause and disease)
|
Autosomal Dominant.Point mutation in either alpha 1 or 2 allele. Mutant protein is produced. 1:3 ratio of normal to mutant collagen for alpha 1 mutation, 1:1 for alpha 2.
Mild to moderate bone deformity, normal sclera. |
|
|
Protein Suicide
|
AKA dominant negative effect. Mutant collagen molecules are poorly secreted from cell and have more rapid rate of degradation.
|
|
|
Overmodification
|
When mutant chains are overmodified by excessive hydroxylation and glycosylationprior to secretion because coiling of helix is slowed via mutation.
|
|
|
Type 1 collagen distribution location and composition.
|
Made up of 2 alpha 1s and one alpha 2:
Skin Tendon Bone Ligaments Cornea |
|
|
Type 2 collagen distribution location
|
Made up of 3 alpha 1s:
cartilage vitreous intervertebral disks |
|
|
Type 3 collagen distribution location and composition.
|
Made up of 3 alpha 1s:
Gut Blood vessels Uterus Other distensible tissue |
|
|
Type 4 collagen distribution location and composition.
|
Made up of three alpha 1s:
Basement membranes, lens capsule |
|
|
Type 5 collagen distribution location and composition.
|
Made up of 2 alpha 1s and 1 alpha 2:
Widespread in small amounts |
|
|
Typical clinical features of OI
|
1) Excessive # of fractures with minimal trauma
2) Bony deformity 3) Defective dentition 4) Hearing loss 5) Blue sclerae 6) Scoliosis |
|
|
EDS common clinical features
|
Hyperextensible joints
joint dislocations Scoliosis Easy bruisability Poor wound healing Abnormal scar formation Soft velvety skin, hyperextensible |
|
|
Vascular EDS
|
Autosomal dominant. Caused by abnormal type 3 collagen (7/8s of molecules are abnormal b/c is a homotrimer) via point mutation of alpha 1.
-Most severe form; can be fatal. -Increased risk for arterial, bowel, or uterine rupture. |
|
|
Kyphoscoliotic EDS
|
Autosomal recessive. Caused by deficiency in lysyl hydroxylase. Ocular type:
-Soft, hyperextensible skin -tall, thin body -Keratoconus abnormality of eye -Ocular globe fragility -Intraocular hemorrhage -Kyphoscoliosis |
|
|
Achondrogenesis
|
Severe end type 2 collagen problem. Autosomal dominant, usually de novo. Caused by overmodification of alpha 1(II) collagen. 7/8s of collagen molecules are abnormal.
-Lethal condition with severe micromelia -hydrops fetalis -short trunk -large head -deficient ossification |
|
|
Hypochondrogenesis
|
Autosomal dominant type 2 collagen problem.
-Lethal -cleft palate, small chin -pulmonary hypoplasia -no vertebral bodies of spine |
|
|
Stickler syndrome
|
Mild end type 2 collagen problem. Autosomal dominant.
-Marfanoid habitus -cleft palate, small chin -severe myopia -anthropathy (joint deterioration) |
|
|
What chromosome is the fibrillin gene on and what disorder does its mutation cause?
|
15. Marfan
|
|
|
Achondroplasia
|
Autosomal dominant disorder. Usually de novo mutation. Mutation in gene for fibroblast growth factor receptor (FGFR3). Usually a G-A or G-C mutation turning a glycine into an arginine. Most mutable region of DNA.
Most common cause of dwarfism |
