Hiperornitinemia con atrofia gyrata de coroides y retina / Hyperornithinemia with gyrate atrophy of the choroid and retina

La atrofia gyrata de coroides y retina fue descrita por vez primera por Fuchs en el año 1896 como una entidad clínicamente definida. La deficiencia de la enzima ornitina delta aminotransferasa se hereda de forma autosómica recesiva; resulta en incremento plasmático de las concentraciones de ornitina y se asocia con atrofia gyrata de coroides y retina. Se presenta una paciente de 6 años de edad que es llevada a consulta, ya que en la escuela la maestra notaba mala visión de lejos. En un examen inicial del fondo de ojo el oftalmólogo observó cambios sugestivos de distrofia retiniana. En la oftalmoscopia binocular indirecta se encontraron extensas zonas confluentes de atrofia coroidea por fuera de las arcadas vasculares que respetaban el polo posterior; la mácula impresionaba normal. Se realizó un estudio de tomografía de coherencia óptica en dominio espectral en tomógrafo Spectralis que demostró la presencia de edema macular cistoide en ambos ojos. La determinación de niveles de ornitina en sangre arrojaron niveles muy elevados de este aminoácido (975 µmol/mL). Con todos estos hallazgos se llegó al diagnóstico de hiperornitinemia y atrofia gyrata de coroides y retina. Se indicó tratamiento dietético y vitamina B6 oral a pesar de que no se ha obtenido hasta el momento reducción significativa de los niveles de ornitina en plasma(AU)

Gyrate atrophy of the choroid and the retina was first described by Fuchs as a clinically defined condition in 1896. Human hereditary deficiency of ornithine aminotransferase activity is transmitted as an autosomal recessive trait and results in increased level of plasma ornithine and is associated with gyrate atrophy of the choroid and the retina. A 6-year-old girl was taken to the ophthalmologist’s because of her far poor vision detected by her teacher at the school. In the initial eye fundus examination the ophthalmologist observed some changes indicating retinal dystrophy. The indirect binocular funduscopy revealed extensive areas of choroidal atrophy outside the vascular archades respected the posterior pole whereas the macula impressed as normal. Cystoid macular edema was evident in both eyes according to the results of the optic coherence tomography performed with Spectralis tomograph. The aminoacid analysis revealed high serum ornithine level (975 µmol/mL). The clinical diagnosis of the patient was consistent with hyper-ornithinemia and gyrate atrophy of the choroid and the retina. She was treated with vitamin B6 and dietary supplementation but no significant reduction on her serum ornithine level was observed(AU)

Gyrate Atrophy of the Choroid and Retina Diagnosed by Ornithine-delta-aminotransferase Gene Analysis: A Case Report

A pair of 19-year-old female identical twins was referred to our hospital with progressive visual loss. They exhibited bilateral chorioretinal atrophy involving the midperiphery on fundoscopy and fluorescein angiography. Bilateral visual field constriction was noted on dynamic Goldmann perimetry, and a markedly impaired response was observed on both photopic and scotopic electroretinograms. Cystoid macular edema was identified in both eyes on optical coherence tomography. Plasma levels of ornithine were elevated. Based on these observations, the patients were diagnosed with gyrate atrophy of the choroid and retina. The clinical diagnosis was confirmed by mutation analysis of the ornithine-delta-aminotransferase (OAT) gene. Patients were treated with a pyridoxine supplement (300 mg/day) and an arginine-restricted diet to lower plasma levels of ornithine, which were successfully reduced without progression of chorioretinal atrophy for 15 months. Our report describes the first case of gyrate atrophy in the Korean population diagnosed by OAT gene analysis and treated with vitamin B6 dietary supplementation.

Two Cases of HHH Syndrome in Siblings

Hyperornithinemia-hyperammonemia-homocitrullinuria(HHH) syndrome is a rare autosomal recessive disorder caused by a defect in the urea cycle. Protein intolerance, mental retardation, seizure, ataxia, and stupor are characteristic symptoms. Patients showing these symptoms may also present symptoms of acute hepatic disease at the same time. When fed with a high protein diet, they may refuse to eat, vomit, become lethargic, or go into coma. After childhood, most patients avoid meats or milk spontaneously and eat a low protein diet. The liver and spleen are normal or slightly enlarged. The coagulation time is prolonged and sometimes there is a deficiency in factor VII and X. Treatment is aimed at preventing hyperammonemia after meals by restricting daily protein intake to 1.2 g/kg/day and this lowers serum ornithine concentration. Prolonged ornithine supplement(0.5 to 1.0 mM/kg/day; i.e., 66 to 132 mg/kg/day divided into three doses) improved patients' protein intolerance and accelerated growth. Since Shih and coworkers first reported this syndrome in 1969, there have been 40 cases reported worldwide but not yet in Korea. We, for the first time in Korea, report two cases of HHH syndrome in brothers.