3-Methyl glutaconic aciduria in Iraqi Jewish children may be misdiagnosed as cerebral palsy

Neuro-Ophthalmic Phenotype of OPA3

BACKGROUND

Type III 3-methylglutaconic aciduria (OPA 3) is a neuro-ophthalmologic syndrome consisting of early-onset bilateral optic atrophy. Since Costeff described the phenotype of 19 patients in 1989, several reports described approximately 50 patients, but most of them lack details about neuro-ophthalmic phenotype. Our aim was to characterize the clinical neuro-ophthalmic phenotype of this syndrome.

METHODS

Nine patients underwent meticulous visual function history and medical documents' review. Results of best-corrected visual acuity (VA), color vision, visual field (VF), ocular motility, pupillary reaction, slit-lamp, and dilated fundus examinations were recorded. Optical coherence tomography (OCT) was performed whenever possible.

RESULTS

The average VA was 1.4 ± 0.8 logarithm of the minimum angle of resolution. Poor vision was the presenting symptom in 5 patients. Six patients had decreased VA and variable degrees of optic atrophy. Humphrey VF testing of 7 patients revealed generalized depression in 5 and a cecocentral defect in 2. All patients demonstrated dysmetric saccades. Four patients had strabismus, 3 with exotropia, and one with esotropia. Seven patients had nystagmus. Ocular motility abnormality is possibly the result of cerebellar atrophy that was found in MRI studies of our patients. OCT of the retina was possible in 6 patients and revealed retinal nerve fiber layer (RNFL) thinning as well as average retinal thinning. Three patients, in whom ganglion cell layer-inner plexiform layer (IPL) measurement was possible, also showed diffused thinning.

CONCLUSIONS

This study compiled data regarding neuro-ophthalmic manifestation of OPA 3 Type III patients. Contrary to established literature, poor vision was the presenting symptom in only 50% of our patients. This is the first report of OCT findings in 3MGA patients. The results demonstrated diffused thinning of the RNFL and ganglion cell complex-IPL with correlation to VA, which is in contrast to OPA1 patients in whom the most severe thinning is at the level of the papillomacular bundle. Average retinal thinning was identified at second and third decades of life, possibly resulting from early ganglion cell loss. These results may contribute to visual prognosis, and OCT may help monitor experimental therapies.

Evaluation of the child with cerebral palsy

Cerebral palsy (CP) is a common problem, occurring in about 2 to 2.5 per 1000 live births. The diagnosis of CP is based upon a history of abnormal motor development that is not progressive coupled with an examination (e.g. hypertonicity, increased reflexes, clonus) "placing" the lesion in the brain. In order to establish that a brain abnormality exists in children with CP that may, in turn, suggest an etiology and prognosis, neuroimaging is recommended with magnetic resonance imaging preferred to computed tomography. Metabolic and genetic studies should be obtained if there are atypical features in the history or on the examination. Detection of a brain malformation in a child with CP might suggest an underlying genetic or metabolic etiology. As cerebral infarction is high in children with hemiplegic CP, diagnostic testing for coagulation disorders should be considered. However, there is insufficient evidence at present to be precise as to what studies should be ordered. An electroencephalogram is not recommended unless there are features suggestive of epilepsy or a specific epileptic syndrome. As children with CP may have associated deficits of mental retardation, ophthalmologic and hearing impairments, speech and language disorders and oral-motor dysfunction, screening for these conditions should be part of the initial assessment.

A case of 3-methylglutaconic aciduria misdiagnosed as cerebral palsy

3-Methylglutaconic aciduria is a rare hereditary metabolic disorder characterized by increased urinary excretion of 3-methylglutaconic and 3-methylglutaric acids. Four clinical forms are recognized. This study presents the case of a 5-year-old male with type IV 3-methylglutaconic aciduria, initially diagnosed as "static encephalopathy." The slow evolution and other clinical characteristics, together with cerebral magnetic resonance imaging (MRI) findings, eventually directed the diagnosis to organic aciduria that was confirmed by urine test. This study proposes that the clinical criteria for childhood cerebral palsy should be rigorously respected; neuroimaging studies, particularly MRI, should be conducted to confirm the diagnosis, especially in atypical cases.