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Chapter 8: Crystal arthropathies 371

Marfan’s syndrome Management
β-blockers have been shown to slow aortic dilata-

Definition
tion, and lifelong therapy is recommended by the
Inherited condition resulting in abnormalities of con-
European Society of Cardiology.
nective tissue causing anomalies in the musculoskeletal, At least annual echocardiograms are required with
cardiovascular and ocular systems.
consideration of prophylactic aortic root replacement
prior to the development of critical dilatation.
Incidence Dislocatedlensesarenotremovedunlessconventional
1in 15,000. visual correcting aids are ineffective.
Orthopaedic intervention may be required.

Genetic counselling should be offered where appro-

Aetiology/pathophysiology priate.
Inherited in an autosomal dominant fashion. Mutations
occur in the FBN1 gene that codes for the extracellular
matrix glycoprotein fibrillin and is on the long arm of Ehlers–Danlos syndrome
chromosome 15. FBN1 mutations also occur in milder
Definition
phenotypes with features overlapping Marfan’s pheno-
An inherited group of conditions resulting from a weak-
type.Twenty-five per cent of cases represent new muta-
ness in collagen.
tions.
Aetiology/pathophysiology
Clinical features At least 10 variants of this condition have been described
The phenotype is variable and unrelated to the FBN1 inherited in a variety of fashions (autosomal dominant,
mutation. autosomal recessive and X-linked recessive). The under-
Musculokeletal: Patients have elongated and asym- lyingpathologyisanabnormalityinskin,jointandblood

metrical faces with a high arched palate. There is a vessel collagen resulting in tissue weakness. Some of the
reduced upper to lower body segment ratio and an subtypes have been mapped to mutations in the collagen
arm span that exceeds the patient’s height. Long thin genes.
fingersandtoesaretermedarachnodactyly.Scoliosisis
common along with pectus excavatum (funnel chest).
Clinical features
Cardiovascular system: There is degeneration of the

There is hyperextensible skin with normal elastic recoil,
media of blood vessel walls:
hypermobile joints, and fragility of blood vessels causing
1 Dilation of the aortic valve ring producing regurgi-
bruising and occasionally aortic dissection and rupture.
tation.
Hypermobility can lead to early osteoarthritic changes
2 Mitral valve prolapse and associated mitral valve
and damage to the joints. Genetic counselling should be
regurgitation.
offered where appropriate.
3 Aneurysm formation may occur, usually in the as-
cending aorta, which may be followed by dissection
and/or rupture. Crystal arthropathies
Ocular: Weakness of the suspensory ligament of the

lens may cause an upward lens dislocation (ectopia
Crystal-induced arthropathy may result in various dis-
lentis).
ease patterns:
Monosodium urate crystals cause acute gout and

Investigations chronic tophaceous gout.
The diagnosis is clinical and can be based on clinical cri- Calcium pyrophosphate causes pseudogout.
teriascoring. Once diagnosed patients require periodic Crystallised injected corticosteroids may result in ia-
aortic imaging to detect early dilation. trogenic acute synovitis.