• Iris: Abnormalities of the iris range from mild hypoplasia to almost complete absence [1]. In the most severe cases, the iris may be reduced to a small portion of residual tissue found only on ultrasound biomicroscopy or gonioscopy [2][4]. The mildest phenotypes may show a normal pupil size with the iris present but abnormal [2] [4]. There may also be loss of the surface architecture [1] [13]. Other changes in the iris can include iris ectropion, colobomatous lesions, and eccentric pupil [14] [15].
• Lens: Cataracts are present in 50-85% of cases [2] and frequently occur at a young age [16][3]. Lens dislocations infrequently occur [1]. Opacities can be due to the persistence of the pupillary membrane or remnant foetal vascularization within the anterior lens capsule [2].
• Cornea: Approximately 20% of patients have keratopathy associated with aniridia [17]. Keratopathic changes begin with peripheral vascularization and thickening that gradually spreads to involve the whole of the cornea [3] [18] and resulting in corneal ulceration, subepithelial fibrosis and erosions [4].
• Optic nerve and retina: Hypoplasia of the optic nerve is reported in up to 10% of cases [5].
• Glaucoma: The incidence of glaucoma in aniridia is common and ranges from 6-75% [1], with the risk generally accepted as 50% [4]. Congenital glaucoma is rare [19].
• Strabismus, ptosis and refractive errors: Ptosis is found in up to 10% of cases [2], with strabismus presenting as esotropia also common [18]. Myopia and hypermetropia are not uncommon [1].

Systemic defects

• Hearing: Difficulties can arise from auditory processing deficits due to abnormal interhemispheric transfer [1].
• CNS: Olfactory deficits are the most common [20], and abnormalities of the cerebellum, corpus callosum, anterior commissure, olfactory bulb and pineal gland have also been demonstrated [20] [21].
• WAGR syndrome: This syndrome is the most common of the aniridia syndromes and involves Wilms tumor, genitourinary abnormalities and mental retardation [1] [4].
• Gillespie syndrome: A rare variant, these cases are associated with mental retardation and cerebellar ataxia [22].

• Asymptomatic

  AML is predominantly asymptomatic, but may present with different symptoms depending on the size and position. Patients often have flank pain and microscopic or macroscopic haematuria. [ugeskriftet.dk]

  Aniridia is typically asymptomatic. Treatment of PAX6-associated ocular complications is likely to include all of the following EXCEPT: A. Penetrating keratoplasty B. Anterior vitrectomy C. Glaucoma shunt D. [ophthalmologyreview.org]

  In addition to underreporting of asymptomatic or undiagnosed keratopathy by subjects, another possible explanation for our lower value for reported keratopathy is the age of the subjects, with a mean age of 25 years at the time of survey. [dovepress.com]

  Rarely an asymptomatic parent may be mosaic for such a deletion; thus, it is appropriate to offer FISH testing or deletion testing to both parents. [eyewiki.aao.org]

• Surgical Procedure

  Clinical examination of two of sisters revealed corneal scarring, bilateral aniridia with severe glaucoma that required multiple surgical procedures to control intraocular pressure. [ncbi.nlm.nih.gov]

  The study also showed that low rates of adverse events were connected with the device or the surgical procedure. [mdmag.com]

  The artificial iris, which is made of foldable medical-grade silicone, is placed during a surgical procedure. [empr.com]

  The study showed low rates of adverse events associated with the device and surgical procedure. [medscape.com]

• Swelling

  Increased intraocular pressure, blood leakage in the eye, swelling of the center of the retina (cystoid macular edema), secondary surgery, corneal swelling, iritis, and retinal detachment included complications pertaining to the surgical procedure. [mdmag.com]

  Complications associated with the implant procedure included increased intraocular pressure, blood leakage in the eye, cystoid macular edema, secondary surgery, corneal swelling, iritis, and retinal detachment. [medscape.com]

  […] salivary glands Fine hair on body (lanugo) Thinning of hair on head, dry and brittle hair Cavities, or discoloration of teeth, from vomiting Muscle weakness Yellow skin (in context of eating large amounts of carrots) Cold, mottled hands and feet or swelling [nationaleatingdisorders.org]

  Lane: Just a little swelling from the fluid that we used to close the wound. There we have it, at the end looks good. [cybersight.org]

  […] discoloration of the fingers Hair that thins, breaks or falls out Soft, downy hair covering the body Absence of menstruation Constipation and abdominal pain Dry or yellowish skin Intolerance of cold Irregular heart rhythms Low blood pressure Dehydration Swelling [mayoclinic.org]

• Collapse

  The disadvantages of the procedure are the possibility of vitreous loss, scleral collapse, choroidal or retinal detachment and endophthalmitis [1, 13]. [hindawi.com]

• Macula

  Retina, macula and optic nerve: The retina is the light sensitive layer of the eye, with the macula being the area responsible for the central vision. The optic nerve carries signals from the eye to the brain. [medindia.net]

  […] development or by the appearance of other eye diseases such as cataracts (opacity of the lens), lens dislocation, lesions of the horny or superficial layer of the eye (which produces alterations in the refraction of light), lesions of the optic nerve or the macula [comunidad.madrid]

  Aniridia is a rare panocular disorder affecting the cornea, anterior chamber, iris, lens, retina, macula and optic nerve. It occurs because of mutations in PAX6 on band p13 of chromosome 11. [ncbi.nlm.nih.gov]

• Photophobia

  A 15-year-old woman with congenital bilateral partial aniridia, cataracts, and intense photophobia presented to the Cornea and Refractive Surgery Unit of the Ophthalmology Department. [ncbi.nlm.nih.gov]

  The patient has photophobia (may be wearing sun-glasses) and nystgmus (usually pendular type). The iris are completely or rudimentary. The edges of the lens are clearly visible. There may be cataract with or without subluxation. [mrcophth.com]

  Clinical features: Symptoms: markedly decreased visual acuity, photophobia, dry eye symptoms associated with severe ocular surface disease (eg, pain, discomfort, etc) Signs: Total absence of the iris is rare Careful gonioscopic examination usually reveals [columbiaeye.org]

  The most frequent symptoms are: photophobia, or rejection of light, severe decrease in visual acuity (even less than 20/200 in some cases) and rapid, involuntary and uncontrolled movements of the eyes, called nystagmus. [comunidad.madrid]

• Strabismus

  Basic and Clinical Science Course, Section 6: Pediatric Ophthalmology and Strabismus. American Academy of Ophthalmology, 2015. [ophthalmologyreview.org]

  […] other eye diseases such as cataracts (opacity of the lens), lens dislocation, lesions of the horny or superficial layer of the eye (which produces alterations in the refraction of light), lesions of the optic nerve or the macula, amblyopia, glaucoma or strabismus [comunidad.madrid]

  Copyright © 2011 American Association for Pediatric Ophthalmology and Strabismus. Published by Mosby, Inc. All rights reserved. [ncbi.nlm.nih.gov]

  Ocular movements were normal and no strabismus was detected. Slit lamp examination disclosed clear corneas and aniridias in both eyes (Figure 1). Peripheral corneal neovascularization, which is usually present in cases of aniridia, was not observed. [healio.com]

  […] can be achieved if macular hypoplasia is not severe.  Strabismus surgery is indicated at an early age. 23. [slideshare.net]

• Esotropia

  Six month after the operation visual acuity in the right eye improved to 0.9 with +1.25Dsph and maintained stable in left eye, with complete elimination of esotropia and signs of binocular vision restoration. [ncbi.nlm.nih.gov]

  SIGNS  Photophobia  Nystagmus (Pendular)  Strabismus (Esotropia) 11. CORNEA  Corneal vascularisation  Epithelial ulcers  Aniridic keratopathy  Arcus juvenilis  Microcornea 12. [slideshare.net]

  She then developed a consecutive esotropia and underwent bilateral medial rectus recessions with inferior transpositions and left inferior oblique anteriorization at 7 years of age. [hindawi.com]

  Strabismus, ptosis and refractive errors: Ptosis is found in up to 10% of cases, with strabismus presenting as esotropia also common. Myopia and hypermetropia are not uncommon. [symptoma.com]

• Osteoporosis

  Bone fractures: Patients whose bones have not fully grown yet have a significantly higher risk of developing osteopenia, or reduced bone tissue, and osteoporosis, or loss of bone mass. Around 1 in 10 cases are fatal. [medicalnewstoday.com]

  Other complications of anorexia include: Anemia Heart problems, such as mitral valve prolapse, abnormal heart rhythms or heart failure Bone loss (osteoporosis), increasing the risk of fractures Loss of muscle In females, absence of a period In males, [mayoclinic.org]

  She also had a history of osteoporosis and hypercholesterolemia. Her mother had relapsing remitting multiple sclerosis in addition to aniridia. The proband of family 4 had bilateral aniridia, atrial septal defect and thyroid nodules. [spandidos-publications.com]

• Nystagmus

  Patients have a poor prognosis of ocular function because of a high incidence of cataracts, glaucoma, corneal pannus, nystagmus, and foveal hypoplasia. [accessanesthesiology.mhmedical.com]

  The twins' father presented with congenital aniridia, nystagmus and cataract at birth, while the twins presented with congenital aniridia and nystagmus. A novel mutation c.888 insA in exon 10 of PAX6 was identified in all affected individuals. [ncbi.nlm.nih.gov]

• Ataxia

  Etiology classic aniridia Gillespie syndrome: triad of partial aniridia, ataxia and learning disability WAGR syndrome multisystemic smooth muscle dysfunction syndrome Genetics Classic aniridia is found with various PAX6 loss-of-function mutations 1. [radiopaedia.org]

  GILLESPIE SYNDROME  This is a rare, genetic condition which can cause Aniridia and cerebella ataxia.  Cerebella ataxia affects the parts of the brain responsible for co-ordination, balance and muscle tone.  Cerebella ataxia can cause problems with [slideshare.net]

  The extraocular features are non-progressive cerebellar ataxia and psychomotor delay [ 16 ]. Several cases of Gillespie syndrome have been reported [ 17 – 39 ]. [journals.plos.org]

  Neurologic signs include marked motor delay, hypotonia, disabling ataxia, and usually mental retardation. The combination with tetralogy of Fallot and/or cardiomyopathy has been reported. [accessanesthesiology.mhmedical.com]

• Cerebellar Ataxia

  […] paired box 6 Chromosome 11 Chromosomal band p13 Imprinted Unknown Genomic reference NG_008679.1 Transcript reference NM_000280.3 Exon/intron information NM_000280.3 exon/intron table Associated with diseases AN, AN-1, ID, Peters, WAGR, WAGRO, aniridia, cerebellar [databases.lovd.nl]

  The extraocular features are non-progressive cerebellar ataxia and psychomotor delay [ 16 ]. Several cases of Gillespie syndrome have been reported [ 17 – 39 ]. [journals.plos.org]

• Irritability

  Besides the optical constrictions patiens also often suffer from the disfiguring appearance, since people often react irritated to a person with a deformed or missing iris. [humanoptics.com]

  Aniridia-related keratopathy — Irritation of the eye’s cornea. Optic nerve problems — Problems involving the nerve that sends images to the brain. [allaboutvision.com]

  I also take ’tear’ drops to help with fluid production in the eye to prevent dry eye and irritation. Cause s of Aniridia Congenital Aniridia is caused by a genetic mutation. The affected gene is known as PAX6. [sineadkane.ie]

  […] include repeated weighing or measuring the body Frequent checking in the mirror for perceived flaws Complaining about being fat or having parts of the body that are fat Covering up in layers of clothing Flat mood (lack of emotion) Social withdrawal Irritability [mayoclinic.org]

  […] inspecting their bodies in the mirror obsession with food, for example, reading cookery books lying about food intake not eating or refusing to eat self-denial lack of emotion or a depressed mood reduced sex drive memory loss obsessive-compulsive behavior irritability [medicalnewstoday.com]

Renal ultrasounds are indicated up to 8 years of age for children exhibiting WAGR or sporadic aniridia without chromosomal abnormality [1]. Cytogenetic testing is used to detect chromosomal abnormalities [2]. The severity of ocular involvement can be assessed by measuring visual acuity, and ophthalmoscopy used to determine iris/pupil abnormalities, optic nerve/foveal hypoplasia and the presence of glaucoma or cataracts [4] [1].

Differential diagnosis includes Peters and Reiger type 1 syndrome, albinism, Gillespie syndrome, iris coloboma and congenital cataract [4] [1].

Glaucoma

A lifelong combination of medical and surgical treatment is required to control intraocular pressure [4]. Medical treatment can involve the use of topical miotics, carbonic anhydrase inhibitors and sympathomimetics [3] [1]. Surgical treatments include the following: goniotomy, trabeculectomy with or without antimetabolites, filtration procedures and trabeculoplasty, but no one treatment has been reliable or shown high efficacy [1] [4].

Cornea

The treatment approach depends on the degree of keratopathy of the ocular surface [4]. Mucolytics, lubricants and drops without preservatives have been shown to be useful [3]. Surgical treatments have a poor prognosis [1] and are reserved for cases with severe reduction of vision [4]. Results of penetrating keratoplasty are very poor [4], and transplantation of amniotic membrane has shown good but only temporary results [4]. Homologous lamellar limbokeratoplasty has given high success rates due in part to the use of systemic immunosuppressants [23]. Use of the Type 1 Boston keratoprosthesis has been very successful [24], but the development or worsening of glaucoma after transplantation limits the long-term success [4].

Lens

Severe opacification necessitates extraction [3] [1], which may be accompanied by an intraocular lens implant [1]. Surgical improvements to vision are limited by other ocular defects [1] and postoperative complications including macular oedema and uveitis [25], determine the surgical technique of choice [1].

Iris

Various techniques have been used to relieve the effects of iris hypoplasia, including contact lenses, eyelid surgery, tattooing of the cornea and implantation of artificial iris devices[3][4]. The development of silicone implants personalized to the colour of the other eye means they can be inserted via a minimal incision in the cornea [4].

Nystagmus and photophobia

These can be relieved by the use tinted spectacles, tinted intraocular lenses and tinted contact lenses [3] [1].

Even with early diagnosis and proper management, aniridia has a poor visual prognosis.

Haploinsufficiency of the PAX6 gene is detectable in about 90% of cases, resulting from genic mutations in two-thirds and chromosomal rearrangements in one-third of cases [4]. Both copies of this gene are required for normal eye development, as it regulates genesis of most of the ocular tissues. PAX6 also regulates development of the olfactory bulb, multiple regions throughout the brain, the gut, pancreas and neural tube [6] [7].

The incidence of aniridia has been reported between 1:40 000 to 1:100 000 [6] and no significant gender or racial bias has been shown [2]. Familial cases of aniridia with dominant inheritance account for approximately two-thirds of patients, with almost complete penetration but variable phenotype [3]. The remaining one-third are sporadic cases [1] [9].

The pathophysiology underlying aniridia is not known with certainty [10]. The epithelium of the normal iris derives from the neuroectoderm of the anterior rim of the optic cup, while the stroma is derived from the mesenchymal tissue of the neural crest [11]. Both stroma and epithelium are deficient in aniridia so defects in the development of either tissue may prevent normal maturation of the other [3]. Another theory suggests that aniridia may result from excessive remodelling, with regular iris formation being followed by inappropriate iris tissue regression [12].

There are no guidelines for the prevention of this inherited disorder.

Aniridia is a rare, panocular, congenital disorder of the tissues of the eye, and results in progressive and severe sight disruption [1]. Characterized by extreme hypoplasia of the iris, aniridia often presents with foveal hypoplasia and nystagmus [2] [3]. Related ocular conditions including glaucoma, cataracts, strabismus and optic nerve hypoplasia result in a variety of visual problems [4] [5].

Aniridia usually presents in infancy [2], and although wide-ranging cerebral defects have been shown [3], hearing and olfactory abnormalities are the most common associated functional deficits [1]. Approximately two-thirds of cases show familial dominant inheritance while the other one-third are sporadic [6]. Sporadic aniridia may show only ocular abnormality, or present in association with a number of systemic disorders [4]. The most common of these is WAGR syndrome that describes the association with Wilms tumor, urogenital abnormalities and mental retardation [1] [3].

All patients have reduced visual function, and regular monitoring is required for early management of a range of debilitating long-term outcomes [2]. Due to the inheritance pattern, genetic counselling is appropriate [1].

Definition

Aniridia is a rare genetic eye condition that is present at birth. It typically affects both eyes and occurs in approximately 1 in 60,000 births.  Rarely, aniridia is caused by trauma to the eye, or sometimes it is not inherited but develops by chance.

Aniridia results in the incomplete formation of the iris (the coloured part of the eye that surrounds the pupil). Aniridia can also affect other parts of the eye including the retina, the cornea and the lens, and causes a wide variety of visual problems.

Cause

• Inherited

Most often, aniridia is inherited and congenital, meaning it is passed from parent to child through their genes and is present at birth. Genes are present in pairs and one of each pair is inherited from each of your parents. A parent can carry one normal and one faulty gene but not develop aniridia because the normal gene makes up for the faulty one. The gene responsible for aniridia is called PAX6. If PAX6 is missing or wrong, it prevents the proper formation of parts of the eye, especially the iris, prior to birth.

Children can inherit genetic conditions through either a dominant or recessive pattern. Dominant conditions are inherited from only one parent. If a parent who carries the aniridia gene has children with a partner who does not carry the gene, there is a 50% chance that any child will have aniridia. A child who does not inherit aniridia cannot pass it on to their children. Nearly two-thirds of congenital cases are caused by a faulty gene inherited this way.

Recessive conditions are inherited from both parents. You would need to inherit the aniridia gene from both parents to develop a recessive type of aniridia. If two parents who carry the gene (but don’t have aniridia) have a child, there is a 25% chance that the child will develop aniridia. Only a very small number of cases of aniridia are caused by a faulty gene inherited this way. Gillespie syndrome is a rare recessive condition that causes aniridia and problems with writing, speech and walking.

• Spontaneous

Approximately one-third of congenital cases occur spontaneously and are not inherited from either parent. The faulty gene starts for the first time in the affected child, and these children are at risk of developing other associated conditions, WAGR syndrome or Miller syndrome.

WAGR are the initials of the problems that can occur in this syndrome:
W: Wilms Tumour is a childhood tumour involving the kidney that usually develops before age 5.
A: Aniridia
G: Genitourinary problems.
R: Retardation (Mental).

Boys and girls can develop WAGR Syndrome, and not all children with the syndrome will have the same types of problems.

Miller syndrome can cause cleft palate and other developmental problems with the face and the limbs. For most children, the eyes are the only affected parts of the body.

Symptoms

The symptoms of aniridia are highly variable and depend on which parts of the developing eye are affected, and some conditions may only develop later on. Some of the more common include:

• Poor vision: Aniridia patients usually have a visual acuity measurement of between 20/80 and 20/200. Some may be legally blind while others are able to drive a car.
• Dry eye: related to problems with tear production, this causes the eyes to feel sore and gritty.
• Amblyopia: Otherwise known as ‘lazy eye’, the image produced by one eye is better than the other.
• Photophobia: Sensitivity to light.
• Nystagmus: Uncontrolled movements of the eyes, usually from side to side. This is very common with aniridia and affects detailed vision. Distance vision is affected more than near vision.
• Glaucoma develops in about 50% of patients, often as they get older and causes damage to the optic nerve due to abnormally high pressure within the eye.
• Fovea hypoplasia: Fovea hypoplasia can make it difficult for children to read and write and see fine detail. 
• Cataract: this is clouding of the lens and can blur vision, and can develop in 50-85% of patients with aniridia.

Diagnosis

Aniridia is usually picked up by a paediatrician during a routine examination, and the child is referred to an ophthalmologist for proper diagnosis. Blood tests may be taken for genetic screening and confirmation of the diagnosis. Children at risk of developing a Wilms tumor will have a regular abdominal ultrasound at least until they are 10 years old. Wilms tumor can be treated successfully if detected early.

Treatment

Treatment depends on the type and severity of the problems, and may include:

• Sunglasses can be used to help with photophobia and glare.
• Contact lenses can improve appearance by mimicking the missing iris, and also reduce glare and improve vision.
• Artificial tears and other lubricants can help with dry eye and maintain corneal health.
• Surgically implanting an artificial iris may be a treatment for some patients.
• Advanced disease of the cornea may require surgery to replace some of the missing developmental cells.
• Treatment for glaucoma can involve surgery and medications.
• Cataracts may require surgery to remove them.

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