QuestionSBA
QuestionChoice
Defects in this most commonly result in Marfan syndrome, which is characterised by disproportionally long and slender limbs, anterior chest wall deformity, lens dislocation, heart murmurs and spontaneous pneumothoraces.
10004533
c
Fibrillin
QuestionChoice
Defects in type III collagen cause Ehlers-Danlos vascular type (also known as Sack-Barabas syndrome). This is associated with features such as thin, fragile, translucent skin, short stature, fragile blood vessels that can rupture, and characteristic facial features.
10004534
d
Type III collagen
QuestionChoice
This is the type of collagen found in most connective tissues, including cartilage, bones, tendons and skin. Defects in type I collagen are associated with numerous conditions, depending on the part of the molecule affected, but these conditions generally affect the aforementioned tissues, not the triad of eyes, ears and kidneys seen with type IV collagen defects.
10004532
b
Type I collagen
QuestionChoice
The probable diagnosis here is Alport syndrome, which has the characteristic triad of renal impairment, eye changes (especially to the lens or cornea), and sensorineural hearing loss. This is due to a defect in one of the genes coding for type IV collagen, a protein needed for the normal functioning of the eyes, ears and kidneys. As these genes are located on the X chromosome, this disorder is often more severe in males.
10004531
a
Type IV collagen
QuestionChoice
Defects in type V collagen cause Ehlers-Danlos classical type (formally called type 1). This is an autosomal dominant condition associated with elastic skin, bruising and joint hypermobility.
10004535
e
Type V collagen
Concept
Chapter
2693
3882
Collagen
Topic
181
Structure and Function of Cells
13453
An 8-year-old boy is brought to his GP by his mother due to slowly progressing hearing loss. Upon investigation, this is found to be bilateral sensorineural hearing loss. Other investigation findings include impaired renal function, haematuria and lenticonus.

Given the probable diagnosis, the patient is likely to have inherited a defect in which of the following proteins?
a