1. SECTIONS:
2. preface & acknowledgements
3. genetics at a glance
4. contacts, support & testing
5. testing & pregnancy
6. newborn screening
7. cancer in the family
8. cardiovascular conditions
9. chromosomal conditions
10. clotting & bleeding conditions
11. cystic fibrosis
12. diabetes
13. fragile X syndrome and other causes of developmental delay
14. haemoglobinopathies
15. hereditary haemochromatosis
16. neurofibromatosis
17. neurological conditions
18. psychiatric conditions
19. genetics in practice
20. emerging genetic technologies
21. glossary

Inherited conditions of connective tissue
with cardiovascular effects

 

A number of connective tissue conditions that follow a pattern of autosomal dominant inheritance are characterised by cardiovascular manifestations. These include Marfan syndrome and Ehlers Danlos syndrome Type IV.

 

(a) Marfan syndrome

 

Clinical features

1. Marfan syndrome affects three major systems: ocular, skeletal and cardiovascular.
2. Ocular effects include myopia, present in most people with Marfan syndrome, and displaced lens, seen in ~50% of cases
3. Skeletal effects include unusually long, slender limbs and fingers (arachnodactyly), hollow and pigeon chest, scoliosis and joint hypermobility
4. Cardiovascular effects are the most life-threatening. These are characterised by a dilatation of the ascending aorta, leading to cardiomyopathy and congestive heart failure, and aortic dissection or rupture, associated with a degeneration of the elastic fibres in the tunica media of the aorta. This is seen in about 90% of cases of Marfan syndrome
5. Exercise and pregnancy, resulting in higher cardiac output, increases susceptibility to aortic rupture.
6. Mitral valve prolapse is also common.

 

Genetics

1. Approximately 15% of cases of Marfan syndrome are due to a spontaneous mutation occurring for unknown reasons at or following conception (de novo cases).
2. Follows a pattern of autosomal dominant inheritance.
3. Is caused by mutations in the FBN1 gene which encodes fibrillin-1, a major protein component of the extracellular matrix structures (microfibrils) found in the aorta, suspensory ligaments of the lens, and in connective tissue of bone.
4. Several hundred different mutations have been found in the fibrillin gene.

 

Prevalence

1. Prevalence is around 1 in 10,000.

 

Management

1. Refer to cardiologist for clinical cardiac assessment.
2. Refer to Genetics Services for counselling regarding implications for other family members and discussion of genetic testing, if available.
3. Treatment involves:
4. > Drug therapy (beta-adrenergic blockers)
   > Advice to avoid heavy exercise and contact sports
   > Regular ophthalmological examination

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