Achard syndrome
Synonyms
1
Overview
Achard syndrome is a syndrome consisting of arachnodactyly, receding lower jaw, and joint laxity limited to the hands and feet. Hypermobility and subluxations of the joints, increased lateral excursion of the patellas and other findings reflect the increased ligament laxity. It is not clear if it is a distinct entity.
Symptoms
- Small thumbs
- Joint laxity in hands
- Joint laxity in feet
- Brachycephaly
- Short mandibular rami
- Slender body
- Long body
- Long narrow skull
- Prominent ears
- Arched palate
- Long arms
- Long legs
- Long slender fingers
- Kyphoscoliosis
- Concave chest
- Flat feet
- Hammer toes
- Subcutaneous fat scanty
- Hyperextensible foot joints
- Hyperextensible hand joints
- Joint dislocations
- Hypotonia
- Nearsightedness
- Crossed eyes
- Myosis
- Rapid involuntary eye movements
- Dislocation of eye lens
- Tremulous iris
- Cataract
- Coloboma
- Heart valve deformities
- Septal defects
- Dilatation of aortic root
- Dilatation of ascending aorta
- Aorta valve incompetence
- Aortic dissection
- Aneurism of pulmonary arteries
- Pulmonary defects
- Kidney defects
- Vertebral fusion
- Cleft lip
- Cleft palate
- Jaw abnormalities
Causes
Achard syndrome is a collection of birth defects that are thought to be due to a gene mutation or defect. It is inherited as an autosomal dominant trait of chromosome 15. It's caused by mutations in gene fibrillin-1, producing changes in elastic tissues, especially of the aorta, eye, and skin. Mutations of fibrillin-1 also cause overgrowth of long bones. In 85% of patients with this disease, the family history confirms Marfan syndrome in one parent as well. In the remaining 15%, a negative family history suggests a fresh mutation, possibly from advanced paternal age.
Treatment
Attempts to stop the degenerative process have met with little success. Therefore, treatment of Marfan syndrome is basically aimed at relieving symptoms — for example, surgical repair of aneurysms and ocular deformities. In young patients with early dilation of the aorta, prompt treatment with beta-adrenergic blockers may decrease ventricular ejection and protect the aorta; extreme dilation requires surgical replacement of the aorta and the aortic valve. Steroids and sex hormones have been successful (especially in girls) in inducing precocious puberty and early epiphyseal closure to prevent abnormal adult height. Genetic counseling is important, particularly because pregnancy and resultant increased cardiovascular workload can produce aortic rupture.
Resources
- NIH