Marfan Syndrome

Marfan syndrome is an inherited disorder that affects Type I collagen (Alpha 2)

Incidence : 1: 10,000

Autosomal dominant

It involves:

• Skeletal
• Ocular
• Cardiovascular
• Pulmonary
• Skin
• Integument
• Dura

Mutation in type 1 fibrillin (FBN 1) : Major component of microfibril

3 Types

• Mis-sense mutation
• Small insertion/ deletion mutation
• exon skipping mutation

Ghent Diagnostic Criteria for Marfan Syndrome

Skeletal manifestation of Marfan Syndrome

Tall stature and disproportionately long, thin limbs (dolichosteromelia)

Smaller than normal upper segment (Head to pubic symphysis) to lower segment (pubic symphysis to the plantar surface)

Arm span that extends the patient’s total height by at least 7.5 cm

Have arachnodactyly (abnormal long and slender digits)

Thumb sign

Opposed thumb projects past the ulnar border of the clenched fist

Wrist sign

The ability of the patient to encircle the opposite wrist with the thumb and small finger with the thumb overlapping the distal phalanx of the small finger

Cross over leg sign

The ability of the patient to touch the floor with the foot of crossing legs

Joint laxity is another hallmark of the disease

Joint hypermobility signs

1. Apposition of thumb to flexor aspect of the forearm
2. Passive dorsiflexion of MCP to 90 degrees
3. Hyperextension of elbow > 10 degrees
4. Hyperextension of knee > 10 degrees
5. Forward flexion with hand flat on the ground

Other Features

Recurrent instability of patella, shoulder, hip, and thumb

Marked flat feet, genu valgum, genu recurvatum

Chest (Pes excavatum, Pes carinatum) due to longitudinal overgrowth of ribs. It decreases total lung capacity, forced vital capacity, and forced expiratory volume which is further compromised by Scoliosis

Spinal Deformity

• Thoracic lordosis
• Thoracic-lumbar kyphosis
• Flat back deformity
• Spondylolisthesis
• Scoliosis

Treatment Options

Bracing is recommended for curves between 15°-25°

If progress > 40°: Spinal fusion + autologous bone graft + rigid fixation

Caution:

• Small pedicle width and laminar thickness in the patient
• Widened transpedicular distance in the lumbar spine

Pre-operative cardiac evaluation is critical

Acetabular protrusion

Treatment recommendation is difficult to make as lack of direct relationship between it and hip symptomatology

Ductal ectasia

It causes low back pain and headache

Occurs in most caudal positions of the spinal column

Posterior laminectomy is done to relieve back pain secondary to ductal ectasia

See also: Klippel Feil Sundrome