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Ornithine aminotransferase deficiency(GACR)

MedGen UID:
6695
Concept ID:
C0018425
Disease or Syndrome
Synonyms: GACR; Girate atrophy of the retina; Gyrate atrophy; Gyrate atrophy of choroid and retina; Hyperornithinemia with gyrate atrophy of choroid and retina; OAT deficiency; OKT deficiency; Ornithine ketoacid aminotransferase deficiency
SNOMED CT: Gyrate atrophy (314467007); Gyrate atrophy of choroid and retina (314467007)
Modes of inheritance:
Autosomal recessive inheritance
MedGen UID:
141025
Concept ID:
C0441748
Intellectual Product
Source: Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in individuals with two pathogenic alleles, either homozygotes (two copies of the same mutant allele) or compound heterozygotes (whereby each copy of a gene has a distinct mutant allele).
 
Gene (location): OAT (10q26.13)
 
Monarch Initiative: MONDO:0009796
OMIM®: 258870
Orphanet: ORPHA414

Definition

Gyrate atrophy of the choroid and retina (GACR) due to deficiency of ornithine aminotransferase is clinically characterized by a triad of progressive chorioretinal degeneration, early cataract formation, and type II muscle fiber atrophy. Characteristic chorioretinal atrophy with progressive constriction of the visual fields leads to blindness at the latest during the sixth decade of life. Patients generally have normal intelligence (summary by Peltola et al., 2002). See 238970 for another hyperornithinemia syndrome. [from OMIM]

Clinical features

From HPO
Proximal muscle weakness
MedGen UID:
113169
Concept ID:
C0221629
Finding
A lack of strength of the proximal muscles.
EMG abnormality
MedGen UID:
99199
Concept ID:
C0476403
Finding
Abnormal results of investigations using electromyography (EMG).
Hyperornithinemia
MedGen UID:
109343
Concept ID:
C0599035
Disease or Syndrome
Gyrate atrophy of the choroid and retina, which is often shortened to gyrate atrophy, is an inherited disorder characterized by progressive vision loss. People with this disorder have an ongoing loss of cells (atrophy) in the retina, which is the specialized light-sensitive tissue that lines the back of the eye, and in a nearby tissue layer called the choroid. During childhood, they begin experiencing nearsightedness (myopia), difficulty seeing in low light (night blindness), and loss of side (peripheral) vision. Over time, their field of vision continues to narrow, resulting in tunnel vision. Many people with gyrate atrophy also develop clouding of the lens of the eyes (cataracts). These progressive vision changes lead to blindness by about the age of 50.\n\nMost people with gyrate atrophy have no symptoms other than vision loss, but some have additional features of the disorder. Occasionally, newborns with gyrate atrophy develop excess ammonia in the blood (hyperammonemia), which may lead to poor feeding, vomiting, seizures, or coma. Neonatal hyperammonemia associated with gyrate atrophy generally responds quickly to treatment and does not recur after the newborn period.\n\nGyrate atrophy usually does not affect intelligence; however, abnormalities may be observed in brain imaging or other neurological testing. In some cases, mild to moderate intellectual disability is associated with gyrate atrophy.\n\nGyrate atrophy may also cause disturbances in the nerves connecting the brain and spinal cord to muscles and sensory cells (peripheral nervous system). In some people with the disorder these abnormalities lead to numbness, tingling, or pain in the hands or feet, while in others they are detectable only by electrical testing of the nerve impulses.\n\nIn some people with gyrate atrophy, a particular type of muscle fibers (type II fibers) break down over time. While this muscle abnormality usually causes no symptoms, it may result in mild weakness.
Myopia
MedGen UID:
44558
Concept ID:
C0027092
Disease or Syndrome
Nearsightedness, also known as myopia, is an eye condition that causes blurry distance vision. People who are nearsighted have more trouble seeing things that are far away (such as when driving) than things that are close up (such as when reading or using a computer). If it is not treated with corrective lenses or surgery, nearsightedness can lead to squinting, eyestrain, headaches, and significant visual impairment.\n\nNearsightedness usually begins in childhood or adolescence. It tends to worsen with age until adulthood, when it may stop getting worse (stabilize). In some people, nearsightedness improves in later adulthood.\n\nFor normal vision, light passes through the clear cornea at the front of the eye and is focused by the lens onto the surface of the retina, which is the lining of the back of the eye that contains light-sensing cells. People who are nearsighted typically have eyeballs that are too long from front to back. As a result, light entering the eye is focused too far forward, in front of the retina instead of on its surface. It is this change that causes distant objects to appear blurry. The longer the eyeball is, the farther forward light rays will be focused and the more severely nearsighted a person will be.\n\nNearsightedness is measured by how powerful a lens must be to correct it. The standard unit of lens power is called a diopter. Negative (minus) powered lenses are used to correct nearsightedness. The more severe a person's nearsightedness, the larger the number of diopters required for correction. In an individual with nearsightedness, one eye may be more nearsighted than the other.\n\nEye doctors often refer to nearsightedness less than -5 or -6 diopters as "common myopia." Nearsightedness of -6 diopters or more is commonly called "high myopia." This distinction is important because high myopia increases a person's risk of developing other eye problems that can lead to permanent vision loss or blindness. These problems include tearing and detachment of the retina, clouding of the lens (cataract), and an eye disease called glaucoma that is usually related to increased pressure within the eye. The risk of these other eye problems increases with the severity of the nearsightedness. The term "pathological myopia" is used to describe cases in which high myopia leads to tissue damage within the eye.
Night blindness
MedGen UID:
10349
Concept ID:
C0028077
Disease or Syndrome
Inability to see well at night or in poor light.
Blindness
MedGen UID:
99138
Concept ID:
C0456909
Disease or Syndrome
Blindness is the condition of lacking visual perception defined as visual perception below 3/60 and/or a visual field of no greater than 10 degrees in radius around central fixation.
Posterior subcapsular cataract
MedGen UID:
163646
Concept ID:
C0858617
Disease or Syndrome
A type of cataract affecting the posterior pole of lens immediately adjacent to ('beneath') the Lens capsule.
Foveoschisis
MedGen UID:
436160
Concept ID:
C2674407
Finding
Splitting of the retinal layers in the macula.
Visual impairment
MedGen UID:
777085
Concept ID:
C3665347
Finding
Visual impairment (or vision impairment) is vision loss (of a person) to such a degree as to qualify as an additional support need through a significant limitation of visual capability resulting from either disease, trauma, or congenital or degenerative conditions that cannot be corrected by conventional means, such as refractive correction, medication, or surgery.
Chorioretinal atrophy
MedGen UID:
884881
Concept ID:
C4048273
Disease or Syndrome
Atrophy of the choroid and retinal layers of the fundus.
Macular thickening
MedGen UID:
893013
Concept ID:
C4072986
Finding
Abnormal increase in retinal thickness in the macular area observed on fundoscopy or fundus imaging.

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVOrnithine aminotransferase deficiency

Recent clinical studies

Etiology

Dong C, Song Z, Meng X, Sun C, Wang K, Yang Y, Qin H, Han C, Zhang F, Zheng W, Gao W
Pediatr Surg Int 2020 Dec;36(12):1443-1450. Epub 2020 Oct 10 doi: 10.1007/s00383-020-04756-3. PMID: 33040172
Vatanavicharn N, Ratanarak P, Liammongkolkul S, Sathienkijkanchai A, Wasant P
Clin Chim Acta 2012 Jul 11;413(13-14):1141-4. Epub 2012 Mar 23 doi: 10.1016/j.cca.2012.03.014. PMID: 22465081
Mehta MC, Katsumi O, Shih VE, Hirose T
Acta Ophthalmol (Copenh) 1991 Dec;69(6):810-4. doi: 10.1111/j.1755-3768.1991.tb02067.x. PMID: 1789102

Diagnosis

Ozcaliskan S, Balci S, Artunay O
J Coll Physicians Surg Pak 2021 Nov;31(11):1354-1356. doi: 10.29271/jcpsp.2021.11.1354. PMID: 34689497
Klinke G, Richter S, Monostori P, Schmidt-Mader B, García-Cazorla A, Artuch R, Christ S, Opladen T, Hoffmann GF, Blau N, Okun JG
J Inherit Metab Dis 2020 Jul;43(4):712-725. Epub 2020 Jan 23 doi: 10.1002/jimd.12213. PMID: 31930732
Santos L, Fiona WJ, Walter JH
J Inherit Metab Dis 2006 Feb;29(1):240. doi: 10.1007/s10545-006-0286-z. PMID: 16601905
Cleary MA, Dorland L, de Koning TJ, Poll-The BT, Duran M, Mandell R, Shih VE, Berger R, Olpin SE, Besley GT
J Inherit Metab Dis 2005;28(5):673-9. doi: 10.1007/s10545-005-0074-1. PMID: 16151897
Ohkubo Y, Ueta A, Ito T, Sumi S, Yamada M, Ozawa K, Togari H
Tohoku J Exp Med 2005 Apr;205(4):335-42. doi: 10.1620/tjem.205.335. PMID: 15750329

Therapy

Santos L, Fiona WJ, Walter JH
J Inherit Metab Dis 2006 Feb;29(1):240. doi: 10.1007/s10545-006-0286-z. PMID: 16601905

Prognosis

Dong C, Song Z, Meng X, Sun C, Wang K, Yang Y, Qin H, Han C, Zhang F, Zheng W, Gao W
Pediatr Surg Int 2020 Dec;36(12):1443-1450. Epub 2020 Oct 10 doi: 10.1007/s00383-020-04756-3. PMID: 33040172
Mehta MC, Katsumi O, Shih VE, Hirose T
Acta Ophthalmol (Copenh) 1991 Dec;69(6):810-4. doi: 10.1111/j.1755-3768.1991.tb02067.x. PMID: 1789102

Clinical prediction guides

Ohkubo Y, Ueta A, Ito T, Sumi S, Yamada M, Ozawa K, Togari H
Tohoku J Exp Med 2005 Apr;205(4):335-42. doi: 10.1620/tjem.205.335. PMID: 15750329
Ramesh V, Gusella JF, Shih VE
Mol Biol Med 1991 Feb;8(1):81-93. PMID: 1682785
Vannas-Sulonen K, Vannas A, O'Donnell JJ, Sipilä I, Wood I
Acta Ophthalmol (Copenh) 1983 Feb;61(1):9-19. doi: 10.1111/j.1755-3768.1983.tb01389.x. PMID: 6858648

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