Alex V. Levin

BASICS

DESCRIPTION

• Peters anomaly is characterized by a congenital corneal opacity associated with a posterior defect in Descemet’s membrane and endothelium. Although usually central, the opacity may be eccentric.

• Variable degrees of iris and lenticular adherence to the posterior cornea may be present.

• May be isolated or associated with other ocular malformations or systemic syndromes.

• Peters plus syndrome describes the concurrence of Peters anomaly, and short stature, with or without abnormal ears, and occasionally, cleft lip and palate.

EPIDEMIOLOGY

Incidence

Peters anomaly is a rare disease affecting less than 200,000 people in the US.

RISK FACTORS

• Genetic predisposition

• Maternal alcohol intake during pregnancy has been reported as a feature of fetal alcohol syndrome (1)[C].

Genetics

• Most cases are sporadic, but both autosomal recessive and dominant modes of inheritance have been reported.

• Isolated Peters anomaly has been reported with mutations in the following genes: PAX6 (autosomal dominant), CYP1B1 (autosomal dominant), PITX2/RIEG1 (autosomal dominant), PITX3, FOXE3 (autosomal recessive), NDP (X-linked recessive), and FOXC1 (autosomal dominant) (2)[C].

• Reported chromosomal anomalies include ring chromosome 20, trisomy 13, and partial deletion of 11q (3)[C].

• Mutations in B3GALTL (13q12.3–13.1) can be associated with Peters plus syndrome, which is inherited in an autosomal recessive manner (2)[C].

GENERAL PREVENTION

Genetic counseling and molecular genetic testing

PATHOPHYSIOLOGY

• Several theories have been implicated:

– Failure of lens placode invagination from surface ectoderm during weeks 4–7 of gestation

– Misdirected neural crest migration and abnormal neural crest differentiation (1)

ETIOLOGY

Drug-induced and infectious (congenital cytomegalovirus) etiologies have been implicated, although most cases appear to be genetic or idiopathic (1)[C].

COMMONLY ASSOCIATED CONDITIONS

• Ophthalmologic problems (1)

• Glaucoma occurs in 30–70%

• Microphthalmia occurs in 25–50%

• Iris abnormalities—aniridia, abnormal vascularization, iris coloboma, polycoria, iridocorneal adhesions, microcoria

• Ptosis

• Cataract

• Posterior pole abnormalities—chorioretinal coloboma, staphyloma, retinal dysplasia/dystrophy, persistent ocular fetal vasculature, optic nerve hypoplasia, foveal hypoplasia/aplasia, macular pigment epitheliopathy, macular “coloboma”

• Systemic malformations occur in 60% of cases (1)[C].

• Mental retardation

• CNS malformations

• Craniofacial abnormalities

• Microcephaly

• Seizure disorder

• Autism

• Congenital heart disease

• Genitourinary malformations

• Skeletal abnormalities (Peters plus syndrome)

• Ear defects

• Cleft lip and palate

DIAGNOSIS

HISTORY

• Course of pregnancy and birth history

• Family history

• Additional directed questions are necessary for recognition and treatment of associated conditions (see “Commonly Associated Conditions”).

PHYSICAL EXAM

• Complete ophthalmological examination with attention to posterior surface of cornea and clarity of visual axis

• Complete neurological and physical exam is necessary to assess for associated conditions (see “Commonly Associated Conditions).

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Initial lab tests

• Peters anomaly is a clinical diagnosis.

• Laboratory studies may be warranted depending on the physical examination.

– Growth hormone stimulation testing for possibility of a treatable cause of growth delay

– Thyroid function testing for congenital hypothyroidism

– Urine and lens for cytomegalovirus, serum titers

Follow-up & special considerations

• Karyotype, microarray, and molecular genetic testing for B3GALTL gene when Peters plus syndrome suspected.

• Molecular genetic studies may be performed for isolated Peters anomaly.

Imaging

Initial approach

• Imaging may be performed as necessary for findings on physical examination.

– Ocular ultrasound for evaluation of ocular structures if no view of posterior segment

– Ultrasound biomicroscopy or optical coherence tomography can identify posterior corneal defect

– Echocardiography for congenital heart malformations when indicated

– Abdominal ultrasound examination for renal anomalies when indicated

– Cranial imaging for hydrocephalus or structural brain abnormalities where indicated

– Skeletal survey for Peters plus

Follow-up & special considerations

• Serial plotting of growth and development

• Intense vision follow-up is required to screen for amblyopia and treat accordingly.

• Suggest examination to rule out glaucoma every 6 months as a minimum even if examination under anesthesia required.

Pathological Findings

• Type 1—characterized by central or paracentral corneal opacity with iris strands that arise from the iris collarette and attach to the cornea. Usually unilateral.

• Type 2–includes lens adherence to the posterior cornea, with or without cataract histopathology shows iris stromal fibers attaching to the posterior cornea with an absent Descemet’s membrane and endothelium Bowman’s layer may appear thickened.

DIFFERENTIAL DIAGNOSIS

• Sclerocornea

• Birth trauma from forceps

• Intrauterine keratitis

• Mucopolysaccharidoses

• Congenital hereditary endothelial/stromal dystrophy

• Corneal dermoid

• Herpes simplex keratitis

• Congenital glaucoma

• Amniocentesis needle corneal perforation

• Covert or overt postnatal trauma

TREATMENT

MEDICATION

Medical treatment of glaucoma

ADDITIONAL TREATMENT

General Measures

The goal of ophthalmological treatment is to maximize vision and minimize amblyopia.

Issues for Referral

• Infant Development Program—appropriate developmental assessment may be helpful if indicated.

• Genetic consultation and counseling—helpful if a heritable disorder is suspected

• Pediatric ophthalmologist—management of amblyopia and refractive error, cataract, and glaucoma

• Cornea specialist—keratoplasty may be indicated.

• Low-vision specialist

• Endocrinologist—if endocrine problems are suspected

Additional Therapies

Additional therapies may be performed as indicated for the associated conditions of Peters anomaly.

SURGERY/OTHER PROCEDURES

• The indication for surgery in patients with Peters anomaly is controversial—considerations include whether monocular or binocular, age, and visual prognosis (1)[C].

• Keratoplasty

– Optical iridectomy (sector) has been used as an alternative to penetrating keratoplasty.

– The degree of visual deprivation depends on the size and location of the ocular opacity.

– When the opacity is small, gradual clearing may occur.

– When the opacity is dense, and, especially if bilateral, penetrating keratoplasty is likely indicated.

– This should be considered at age 1–6 months. One must balance high failure rate and technical difficulties if too young versus high amblyopia rate if too old.

– The probability of first grafts remaining clear for 10 or more years was 35% according to one study (4)[C].

• Glaucoma surgery

– Multiple procedures and adjunctive medical therapy are often required.

– Trabeculotomy or goniotomy may be difficult technically and have high failure rates due to maldevelopment of drainage structures.

– Trabeculectomy and tube implantation may be preferred.

– Cyclodestructive procedures as last option

• Lensectomy/vitrectomy

– May be indicated for patients with cataract

– Lens may spontaneously come out at penetrating keratoplasty.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• Regular follow-up care for visual rehabilitation, corneal graft management, and glaucoma management as needed

• Regular follow-up with a pediatrician to manage the patient’s other congenital abnormalities as necessary

Patient Monitoring

Patient monitoring as necessary for ophthalmological and associated systemic issues.

PATIENT EDUCATION

• www.pgcfa.org (Pediatric Glaucoma and Cataract Family Association)

• www.rarediseases.org/ (National Organization for Rare Diseases)

• www.petersanomaly.org/ (Peters Anomaly Support Group)

PROGNOSIS

• Systemic prognosis depends on associated systemic problems.

• After penetrating keratoplasty:

– ∼20% of eyes achieve acuities of 20/200 or better.

– ∼40% of eyes achieve light perception (LP) or no light perception (NLP) vision.

– The remaining eyes achieve 20/300 to hand motion vision (1)[C].

• Prognosis is more promising in bilateral cases.

COMPLICATIONS

Amblyopia and decreased vision or blindness from glaucoma

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