Aniridia

Classification according to ICD-10
Q13.1	Absence of the iris (congenital) aniridia
ICD-10 online (WHO version 2019)

Aniridia is a very rare congenital disease that causes the absence or hypoplasia of the iris of the eye .

Often this is also associated with an incorrect development of the retina at the rear end of the eyeball, which means loss of vision.

Aniridia

Synonyms are iris aplasia and irideremia .

The first description comes from the Würzburg doctor Gutbier, quoted from G. Rindfleisch.

root cause

The disease are mutations in PAX6 - gene on the AN2 region on the chromosome 11 locus p13 based. It is required for a chain of other genetic processes that affect the development of the eye and other structures.

Aniridia is a heterozygous disease, which means that only one of the two chromosomes 11 is involved. If both are affected ( homozygous ), the result is a generally fatal condition, with the lack of complete eye primordia.

Several different mutations can affect the PAX6 gene: some of them seem to suppress the function of the gene more than others, which leads to different degrees of severity of the disease. In some people with aniridia, for example, only a relatively small part of the iris is absent, they have no foveal tissue atrophy and their vision is relatively normal. Therefore, it is believed that the genetic defect results in less heterozygous insufficiency in these individuals, which is to say that gene function is good enough to result in a more compromised appearance.

distribution

The frequency is given as 1–9 in 100,000, inheritance is autosomal dominant .

Classification

This congenital disease can be divided into:

• occurring spontaneously , "new mutation". The isolated occurrences of aniridia due to mutations affect the WT1 region on the chromosomes that are adjacent to the AN2 region for aniridia. These patients frequently develop a kidney tumor, the nephroblastoma (also called Wilms tumor). Often people affected by this have a mental disability and abnormality of the reproductive organs (all of this is summarized under the WAGR syndrome).
• familiar . This hereditary form usually has its origin in an autosomal dominant transmission (that is, half of all offspring are affected on average), although there have been cases of rare autosomal recessive transmission.
• isolated , without further malformations or only affecting the eye
• syndromic , in the context of syndromes like
  • Aniridia-patellar aplasia syndrome
  • Aniridia-ptosis-intellectual disability-familial obesity syndrome
  • Gillespie syndrome , synonym: aniridia-cerebellar ataxia-intellectual disability syndrome
  • Rieger syndrome
  • Sommer-Rathbun-Battles-Syndrome , synonym: aniridia - renal agenesis - psychomotor retardation
  • WAGR syndrome , synonym: Wilms tumor aniridia-urogenital anomalies-intellectual disability syndrome
  • Walker-Dyson syndrome , synonym: aniridia - mental retardation

Clinical manifestations

The disease usually affects both eyes. It is to be noted that the iris can hardly be seen externally and can only be recognized as a round stump by a gonioscopy .

Symptoms of the condition can appear both inside and outside of the eyes. Some of them are listed below:

• The stumps of the iris are usually noticeable.
• With partial aniridia, vision may still be good, but vision loss is more common.
• The cornea is cloudy.
• The patient squinted.
• The field of vision narrows as the disease progresses.
• The body size may be reduced.
• Developmental disorders of the genital organs can occur.
• Chromosomal abnormalities are possible.
• Intellectual disabilities may be present.
• Diabetes can occur.
• Certain areas of the brain can be malformed or improperly formed.

therapy

Aniridia patients show an increased risk of developing glaucoma and cataracts ( glaucoma and cataracts ). Therefore, sufferers should seek professional help from an eye specialist. The risk of progressive glaucoma persists from childhood to adulthood, so the doctor and optician should order regular checks and ensure that visual function is maintained (e.g. by prescribing visual aids or promoting light sensitivity).

Since the iris regulates the flow of light that reaches the inside of the eye, aniridia sufferers are usually very sensitive to light. A remedy can be created by tinted glasses or contact lenses with an artificial iris.

Aniridia is also associated with other health or developmental problems, such as nystagmus , cataracts , glaucoma , tissue shrinkage in the fovea , detachment of the lens of the eye , and various corneal and tendon diseases .

In animals

The gene is 95% identical to the gene found in the zebrafish genome . This animal separated evolutionarily from humanity about 400 million years ago; therefore, the PAX6 gene forms an important evolutionary bridge to the ancestors of mankind. Defects in this gene also create a type of aniridia in the eyes of mice and fruit flies .

Aniridia in the public eye

Poster from the fans and 1. FC Union Berlin for the fundraising campaign Seeing Together Union Leben

Since aniridia is one of the very rare eye diseases, details about the disease and its course are hardly known to the public. The fundraising campaign by a club in the 2nd Bundesliga and its fan club brought the problem into a national focus for the first time and gained nationwide attention, which was also reflected in the media.

literature

• AJ Augustin: Ophthalmology. Berlin, 2007, ISBN 978-3-540-30454-8
• F. Grehn: Ophthalmology. Berlin, 30th edition, 2008, ISBN 978-3-540-75264-6

Individual evidence

1. ↑ ^{a b c} aniridia, isolated. In: Orphanet (Rare Disease Database).
2. ↑ Bernfried Leiber (founder): The clinical syndromes. Syndromes, sequences and symptom complexes . Ed .: G. Burg, J. Kunze, D. Pongratz, PG Scheurlen, A. Schinzel, J. Spranger. 7., completely reworked. Edition. tape 2 : symptoms . Urban & Schwarzenberg, Munich et al. 1990, ISBN 3-541-01727-9 .
3. ↑ Gutbier: De Irideremia. Diss. Inaug. From Würzburg, 1834
4. ^ G. beef: Contributions to the history of the development of congenital malformations of the eye. In: Albrecht von Gräfe's archive for ophthalmology. Vol. 37, 1891, p. 192, doi: 10.1007 / BF01947220 .
5. ↑ Aniridia.  In: Online Mendelian Inheritance in Man . (English)
6. ^ Genetics Home Reference
7. ↑ Rare Diseases
8. ↑ aniridia-patellar aplasia syndrome. In: Orphanet (Rare Disease Database).
9. ↑ Aniridia-ptosis-intellectual disability-familial obesity syndrome. In: Orphanet (Rare Disease Database).
10. ↑ Aniridia-cerebellar ataxia-intellectual disability syndrome. In: Orphanet (Rare Disease Database).
11. ↑ Aniridia - mental retardation. In: Orphanet (Rare Disease Database).
12. ↑ Report of the Bundesliga on the painting and donation campaign ( Memento of the original from November 28, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. 
13. ↑ Berliner Zeitung of August 1, 2013: Union is fighting for Martin Dausch's sick child

Web links

• Aniridia pictures
• Aniridie-WAGR self-help group
• Unionforum with Aktion Union see painting with union
• Spiegel online for the Bundesliga match Union vs. Fortuna after the painting action

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !