Hereditary Vitreoretinal Degenerations

Description

The term vitreoretinal degenerations encompass a heterogenous group of conditions that are inherited and potentially have severe visual consequences, necessitating significant retinal surgery. Two, Stickler’s syndrome and familial exudative vitreoretinopathy, are inherited as an autosomal dominant and have been mapped to chromosomes 12 and 11 respectively. Favre-Goldmann syndrome is autosomal recessive. Congenital retinoschisis is inherited as an X-linked recessive and is described elsewhere in this book (see Retinoschisis). There are reports of familial exudative vitreoretinopathy also occurring in an X-linked recessive pattern. These conditions manifest a variety of vitreous and retinal degenerations which can frequently lead to retinal detachment and a loss of sight. Stickler’s syndrome also has systemic complications including midline facial and clefting anomalies, a progressive sensorineural hearing loss, mitral valve prolapse, and skeletal problems such as hyperextensible joints, epiphyseal dysplasia and an arthropathy affecting weight-bearing joints.

Symptoms

The patient may have poor vision due to high myopia, strabismus, amblyopia and early-onset cataract. There may be symptoms associated with retinal detachment and patients with Favre-Goldmann syndrome may complain of night vision difficulties.

Signs

Stickler’s syndrome

The vitreous appears to be optically empty due to syneresis and liquefaction. The patient is usually highly myopic with hyperplastic retinal pigmentary and chorioretinal atrophic changes. Retinal breaks commonly occur which can lead to retinal detachment. Other ocular anomalies include early-onset cataract, dislocated lenses, elevated intraocular pressure and open angle glaucoma.

Favre-Goldmann syndrome

In this condition the vitreous is synerytic but, in contrast to Stickler’s syndrome, it is not optically empty. Peripheral retinal pigmentary changes occur that are similar to those found in retinitis pigmentosa, together with white, dendritic retinal vessels. Again, early-onset cataract can occur.

Familial exudative vitreoretinopathy

Retinal vessels terminate at the equator, and this particularly involves the temporal fundus. This can lead to neovascularisation, vitreous haemorrhage, exudation, which can be profound, and a dragging of the macula and optic disc as in retinopathy of prematurity. Fluorescein angiography delineates the abnormal vessels and areas of poor perfusion. The vitreous is abnormal with bands attached to the retina and a posterior vitreous detachment. Complications include retinal detachment, strabismus and early-onset cataract.

Incidence

All of these conditions are rare.

Differential Diagnosis

Stickler’s syndrome should be differentiated from Wagner’s syndrome, where the ocular findings are identical but the systemic associations are absent, degenerative high myopia and other causes of retinal detachment in younger individuals. Favre-Goldmann syndrome must be distinguished from retinitis pigmentosa. Familial exudative vitreoretinopathy may be confused with retinopathy of prematurity and Coats’ disease.

Management

Additional Investigations

Electrophysiological testing can be a useful investigation tool in these conditions. Electroretinography often shows a loss of the b wave amplitude. Electro-oculography findings are abnormal in Favre-Goldmann syndrome.

Review and Advice

While these conditions themselves cannot be treated, their potential ocular and systemic sequelae, especially retinal breaks and detachment, cataract, glaucoma and strabismus, demand frequent review and prophylactic management where appropriate. In the case of Stickler’s syndrome, a multidisciplinary medical assessment is warranted.

Refractive correction and genetics

Significant refractive errors should be corrected and genetic counselling undertaken.