vitamin-b-12 and Retinal-Diseases

Transcobalamin (TC) transports cobalamin (vitamin B. We report the electrophysiological results of one TC-deficient patient diagnosed at the age of 4 months immediately and continuosly treated by hydroxocobalamin IM. Her visual function was followed by eight ophthalmological assessments, eight flash-ERG, six EOG, one mf-ERG, and seven P-ERG recordings over a 10-year period, between the age of 2y 9 m and 12y 6 m.. Her ophthalmological assessment including visual acuity, fundi, optical coherent tomography (OCT), and retinal nerve fiber layer (RNFL) remained normal. From the age of 2y 9 m to 5y, dark-adapted and light-adapted flash-ERGs, EOGs and pattern-ERG were normal. From the age of 6y 4 m to 12y 6 m, dark-adapted flash-ERGs and EOGs remained normal. Cone a-wave amplitudes remained normal, whereas cone b-wave and flicker-response amplitudes were decreased. At the age of 12y 6 m, mf-ERG N1P1 amplitudes on the central 30° were decreased. From the age of 7y 4 m to 12y 6 m, P-ERG P50 amplitudes were decreased with no N95.. While clinical and anatomical assessments remained normal over a 10-year period, patient's electrophysiological results suggested the progressive onset of a subclinical retinopathy of inner-cone dystrophy type, and a subclinical maculopathy on the central 30° including the ganglion cell layer deficiency on the central 15°, despite continuous intramuscular treatment, RPE and scotopic system remaining normal. The origins of such subclinical retinopathy and maculopathy are unknown and independent of early disease identification and aggressive intramuscular hydroxocobalamin therapy.

Topics: Child; Child, Preschool; Electroretinography; Female; Follow-Up Studies; Humans; Hydroxocobalamin; Infant; Macular Degeneration; Retinal Diseases; Transcobalamins; Vitamin B 12

Topics: Color Vision Defects; Electroretinography; Female; Fluorescein Angiography; Humans; Magnetic Resonance Imaging; Middle Aged; Paresthesia; Retinal Diseases; Tomography, Optical Coherence; Visual Acuity; Vitamin B 12; Vitamin B 12 Deficiency; Vitamin B Complex

To assess and compare longitudinal visual function and retinal morphology in patients with methylmalonic aciduria with homocystinuria, cobalamin C type (cblC), and identified mutations in the MMACHC gene.. Vision function, anterior segment, and fundi were evaluated in patients with homozygous or compound heterozygous MMACHC mutations. Best-corrected visual acuity, full-field electroretinogram (ERG), refractive error, and retinopathy were assessed and compared for different genotypes and ages at onset, defined as early (<1 year of age) or late (>5 years).. We identified 7 patients (homozygous mutation: 6 of 7; compound heterozygous mutations: 1 of 7) between the ages of 3 months and 20.6 years. Six patients were reexamined after 3.2 to 11.5 years (mean, 6.5) Ocular phenotype ranged from normal to severely compromised visual function. Visual acuity was reduced from 0.2 logMAR to counting fingers and from 0.0 to 0.3 logMAR in the early- (3 of 7) and in the late-onset group (4 of 7), respectively. No retinopathy was evident in the late-onset group. Only patients with the homozygous c.547_548 delGT mutations (n = 2) demonstrated advanced retinopathy associated with cone-rod or rod-cone dysfunction. Retinopathy occurred despite systemic treatment for cblC.. Ocular phenotype in patients with cblC is variable. Ocular involvement seems to be correlated with age at onset. Patients with early-onset cblC developed generally progressive retinal disease ranging from subtle retinal nerve fiber layer loss to advanced macular and optic atrophy with "bone spicule" pigmentation. Patients with late-onset disease showed no definite evidence of retinal degeneration.

Topics: Adolescent; Age of Onset; Anterior Eye Segment; Carrier Proteins; Child; Child, Preschool; Disease Progression; Electroretinography; Eye; Female; Fundus Oculi; Genes, Recessive; Heterozygote; Homocystinuria; Humans; Infant; Longitudinal Studies; Male; Metabolism, Inborn Errors; Methylmalonic Acid; Mutation; Oxidoreductases; Phenotype; Retina; Retinal Diseases; Visual Acuity; Vitamin B 12; Young Adult

Topics: Humans; Male; Middle Aged; Retinal Diseases; Transcobalamins; Visual Acuity; Vitamin B 12

Isolated functional methionine synthase deficiency occurs in the cblE and cblG defects of methylcobalamin metabolism and is one of a number of causes of severely elevated plasma homocysteine. Clinical features are predominantly of a neurological nature but also include functional restriction of the visual system manifesting as loss of visual acuity and nystagmus. As yet, the origin and pathogenesis of impaired vision have not been explained.. We investigated a patient who was proven by complementation analysis in cultured fibroblasts to belong to the cblG complementation group. Ganzfeld electroretinograms (ERG) and flash visual evoked potentials (VEP) were recorded over a period of 4 years.. Amplitudes of all International Society for Clinical Electrophysiology of Vision (ISCEV) standard responses were below normal. The greatest reductions were of rod response to 24 microV, of standard combined response (SC) b-wave to 120 microV, of oscillatory potentials (OP) to 5 microV, of cone response b-wave to 35 microV, and of 30 Hz flicker response to 8 microV. Except for SC and cone a-waves at age 2.5 and 3.5 years, as well as cone b-wave at 3.5 years, amplitudes remained at a subnormal level at follow-up examinations. Implicit times were slightly prolonged (SC b-wave 6 ms, OPs 2 ms, cone b-wave 2 ms, 30 Hz flicker 4 ms) or fell within the normal range. Responses of the flash VEP were severely deformed but reproducible.. This is the first report of detailed investigations of the visual system in a patient with isolated methionine synthase deficiency. Reduced oscillatory potentials suggest microvascular damage to the retina through homocysteine. Decreased photoreceptor function as well as ganglion cell loss as indicated by pathological flash VEPs may reflect a cytotoxic impact of homocysteine on neurons of the visual pathway.

Topics: 5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; Electroretinography; Evoked Potentials, Visual; Genetic Complementation Test; Humans; Infant; Male; Retinal Cone Photoreceptor Cells; Retinal Diseases; Retinal Ganglion Cells; Retinal Rod Photoreceptor Cells; Vision Disorders; Vitamin B 12

Topics: Diabetes Complications; Diabetic Retinopathy; Disease; Hematinics; Retina; Retinal Diseases; Vitamin B 12

Topics: Diabetes Complications; Diabetic Retinopathy; Disease; Retina; Retinal Diseases; Vitamin B 12

Topics: Corrinoids; Diabetes Complications; Diabetes Mellitus; Disease; Humans; Retina; Retinal Diseases; Vitamin B 12

Topics: Adjuvants, Pharmaceutic; Diabetes Complications; Diabetic Retinopathy; Disease; Humans; Lipotropic Agents; Retina; Retinal Diseases; Vitamin B 12

Topics: Adrenal Cortex; Adrenal Cortex Diseases; Diabetes Complications; Diabetic Retinopathy; Disease; Humans; Retina; Retinal Diseases; Vitamin B 12; Vitamin B 12 Deficiency

Topics: Blood; Corrinoids; Diabetes Mellitus; Diabetic Retinopathy; Disease; Humans; Retina; Retinal Diseases; Vitamin B 12

Topics: Adrenocorticotropic Hormone; Diabetes Complications; Diabetes Mellitus; Disease; Diterpenes; Humans; Retina; Retinal Diseases; Retinyl Esters; Vitamin A; Vitamin B 12