Risk of thrombosis is increased during any perioperative period and appropriate precaution should be taken peri-operatively (heparin, aspirin, low-molecular weight dextran, compression stockings, etc.). The largest concern is the effects elevated homocysteine has on the vascular system leading to thromboembolic events (stroke, pulmonary embolism, embolus of the iris) that increase the morbidity and mortality of the disease. The central nervous system is often involved, presenting with developmental delay, intellectual disability, movement disorders, and seizures. If the skeletal system is affected, they can be described as having “Marfanoid habitus” which includes excessive height, long limbs, scoliosis, and pectus excavatum. Individuals with Homocystinuria can present with any number of different systemic manifestations. Additionally, the lens zonules of the eye have high cysteine content and are possibly weakened by the reduced level of cysteine. The interference between elastin proteins may also cause alterations of the scleral connective tissue.

This cross-linking interference is thought to contribute to ectopia lentis and the skeletal abnormalities seen in homocystinuria. The alterations to fibrillin and cross-linking modification in elastin may contribute to connective tissue abnormalities and vascular endothelial dysfunction. Increased S-adenosylhomocysteine (SAH), a precursor to homocysteine, impairs methylation reactions and decreased concentrations of cystathionine and cysteine are associated with apoptosis, oxidative stress, and alterations of structural proteins like fibrillin. However, raised homocysteine concentrations interfere with the cross-linking of sulfonhydryl groups in proteins such as those in elastin. The pathophysiology of homocystinuria is not completely understood. Different mutations are associated with variation in the expected phenotype, with some mutations associated with milder, or conversely more severe, disease. Of these mutations, 67% are missense mutations. Ĭystathionine beta-synthase is a protein coded on chromosome 21 (21q22.3) with 164 pathogenic mutations currently identified, the most common being p.Ile278Thr and p.Gl圓07Ser, found in exon 8. Therefore, it is important to test siblings of children who present with homocystinuria. Barring a new sporadic mutation, each parent must be a carrier and each of their children has 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Homocystinuria is inherited in an autosomal recessive manner. Minimum worldwide incidence is estimated to be ~0.38:100,000 and the incidence has been shown to be higher in non-Finnish Europeans (~0.72:100,000) and Latin Americans (~0.45:100,000) and lower in Africans (~0.20:100,000) and Asians (~0.02:100,000). There is no “right” or “wrong” decision, as every person has different needs and priorities. In general, you should only go ahead with surgery if you find the distortion of your vision troublesome at the moment, and not as a preventative measure.The worldwide prevalence of homocystinuria is estimated to be 0.82:100,000 according to clinical records and 1.09:100,000 by neonatal screening. This is reasonable, especially if the vision in the other eye is not affected. However, if the distortion affects your ability to work, drive, read, or perform other important activities, you should consider having an operation. Some patients decide not to have an operation and accept the distorted central vision in the affected eye. If you are not aware of any visual problems, you might not need to have surgery. The main reason to proceed with the operation is to attempt to correct the distortion of your central vision.

Your doctor will help you to decide if surgery is appropriate for you. These will be removed the morning after your surgery. At the end of the operation, we usually put a pad and shield over your eye to protect it. These dissolve naturally over about four to six weeks. They then grasp and gently peel away the epiretinal membrane from the retina. We usually put small stitches in the eye. During the vitrectomy, the surgeon makes tiny cuts in your eye and removes the vitreous from inside.

The only way to treat an epiretinal membrane is by having an operation called a vitrectomy.

Bilateral ectopic pupil