Peters anomaly

Peters anomaly: Anterior Chamber Cleavage syndrome

Peters anomaly was first described in 1906 by a German Ophthalmologist, Dr Alfred Peters. The anomaly affects the eyes of people of both genders and from all ethnic groups. Peters anomaly is a developmental error of early pregnancy (10-16 weeks).

Most cases occur sporadically with no other members of the family having an associated ocular abnormality, but it can be inherited. Peters anomaly is not a single disorder and can be the result of an error in one or more genes or possibly due to environmental influences on the developing eye. Errors (mutations) in several different genes including PAX6, PITX2, CYP1B1, and FOXC1 (Rieger syndrome gene) have been found in individuals with Peters anomaly.

Normally, the cornea, which is the transparent 'window' of the eye, focuses light through the lens onto the retina (a light sensitive film at the back of the eye). Signals are then sent by the optic nerve to the brain for interpretation. The cornea, lens, retina and optic nerve need to work perfectly in harmony for clear vision.

In Peters anomaly the central part of the cornea is hazy and white. This may affect one or both eyes. The corneal opacity is the obvious feature that Dr Peters described but this is now known to be part of a spectrum of abnormal development of the front of the eye. The eye may be abnormal in other ways including the drainage angle of the eye which may be underdeveloped so there is a risk of glaucoma and the lens of the eye may be cloudy (see entry, cataracts). The fellow eye may have a milder developmental anomaly or be more severely affected where only a rudimentary small eye has developed.

A number of features will lead to the actual way the child is affected:

• If the centre area of the cornea is white or cloudy, the cornea will not allow the eye to obtain a clear picture of the world. Light enters the eye but, if both eyes are affected, the child will not be able to clearly see what an object is. They will just be aware that something is there and aware of colours.
• Peters anomaly can be associated with other eye problems that contribute further to reduced vision including glaucoma, nystagmus, microphthalmia, cataracts and retinal detachment.
• As the cloudy area usually affects the centre of the cornea, then even if the cornea is later grafted with a clear donor cornea the eye will be amblyopic (lazy eye). The area of the developing infant brain that responds to signals from the eyes needs to be given information of good quality about the world very early in life for normal eyesight to develop.

A diagnosis of Peters anomaly will be made by examination by an ophthalmologist. Usually, the eye abnormality is detected soon after birth but there may be a delay before the correct diagnosis is made. The clouding of the front of the eye may spontaneously improve over the first few months but it is most important that the child is examined as soon as possible by an ophthalmologist. It is very rare for an ophthalmologist to require a baby to have a general anaesthetic to make a diagnosis but occasionally this may be necessary to make a thorough examination. It is difficult for both parents and specialists to predict how well the child will see. This will become more apparent as the child develops and interacts with their environment.

In cases where Peters anomaly is bilateral (affecting both eyes), surgical intervention may be possible by way of a cornea transplant. However, the process is complicated and very difficult for a child to handle with constant hospital visits and daily eye drops. Great improvement in vision cannot be guaranteed. Other surgery such as an optical iridectomy (making a small window in the iris of the eye under a clear area of cornea) may be helpful in selected cases. Spectacles, with dark lens to help with sun glare, or contact lens can improve use and comfort of eyesight.

In one study, sixty per cent individuals with Peters anomaly of the eye had abnormalities of other organs, in particular the heart or central nervous system. Twenty per cent of cases had developmental delay. Some of the anomalies associated with Peters anomaly occur in a particular pattern and form a recognisable syndrome such as Peters Plus syndrome.

Inheritance patterns
Peters anomaly can be inherited in autosomal dominant or autosomal recessive mode as well as occurring sporadically (with no other associated family members).

Prenatal diagnosis
In most cases there will be no prenatal diagnosis possible. However, in the minority where a gene defect can be identified, there may be a possibility.

Peters Plus syndrome

Peters Plus syndrome: Krause-Kivlin syndrome

Peters Plus syndrome is a rare disorder in which Peters anomaly is usually associated with short limb dwarfism and learning disability.

The cause of the syndrome is not known.

Features of Peters Plus syndrome associated with Peters anomaly may include:

• learning disability in over eighty per cent of cases;
• cleft lip and/or palate in over forty per cent of cases;
• a short or broad head, thin upper lip with smooth philtrum;
• hydrocephalus;
• short hands with tapering or webbing of the fingers;
• heart anomalies (see entry, heart defects);
• cataracts;
• genitourinary abnormalities;
• hearing abnormality;
• hypotonia and lax joints.

Inheritance patterns
Autosomal recessive.

Prenatal diagnosis
As no gene defect has been identified in Peters Plus syndrome, molecular prenatal diagnosis is not yet possible. However, in some cases, dysmorphic features of the fetus can be detected by ultrasound by twenty weeks gestation.

Medical text written January 2006 by Contact a Family. Approved January 2006 by Miss Isabelle Russell-Eggitt FRCS FRCOphth, Consultant Ophthalmic Surgeon, Great Ormond Street Hospital, London, UK.

Further Online Resources
Medical texts in The Contact a Family Directory are designed to give a short, clear description of specific conditions and rare disorders. More extensive information on this condition can be found on a range of reliable, validated web sites and links to them are included in the CD-ROM version of this Directory. Further information on these resources can be found in our Medical Information on the Internet article.

There is no support group for Peters anomaly or Peters Plus syndrome. Cross referrals to other entries in The Contact a Family Directory are intended to provide relevant support for these particular features of the disorder. Organisations identified in these entries do not provide support specifically for Peters anomaly or Peters Plus syndrome. Families can use Contact a Family's Freephone Helpline for advice, information and, where possible, links to other families. Contact a Family's web-based linking service Making Contact.org can be accessed at http://www.makingcontact.org