Costeff syndrome: clinical features and natural history.

Costeff syndrome (CS) is a rare autosomal-recessive neurological disorder, which is known almost exclusively in patients of Iraqi Jewish descent, manifesting in childhood with optic atrophy, ataxia, chorea and spastic paraparesis. Our aim was to study the clinical spectrum of CS and natural history using a cross-sectional study design. Consecutive patients with CS were recruited to the study. Patients were diagnosed based on clinical features, along with elevated urinary levels of methylglutaconic and methylglutaric acid, and by identification of the disease-causing mutation in the OPA3 gene in most. All patients were examined by a neurologist and signs and symptoms were rated. 28 patients with CS (16 males, 21 families, age at last observation 28.6 ± 16.1 years, range 0.5-68 years) were included. First signs of neurological deficit appeared in infancy or early childhood, with delayed motor milestones, choreiform movements, ataxia and visual disturbances. Ataxia and chorea were the dominant motor features in childhood, but varied in severity among patients and did not seem to worsen with age. Pyramidal dysfunction appeared later and progressed with age (r = 0.71, p < 0.001) leading to spastic paraparesis and marked gait impairment. The course of neurological deterioration was slow and the majority of patients could still walk beyond the fifth decade. While visual acuity seemed to deteriorate, it did not correlate with age. CS is a rare neurogenetic disorder that causes serious disability and worsens with age. Spasticity significantly increases over the years and is the most crucial determinant of neurological dysfunction.

Inborn errors of metabolism with 3-methylglutaconic aciduria as discriminative feature: proper classification and nomenclature.

Increased urinary 3-methylglutaconic acid excretion is a relatively common finding in metabolic disorders, especially in mitochondrial disorders. In most cases 3-methylglutaconic acid is only slightly elevated and accompanied by other (disease specific) metabolites. There is, however, a group of disorders with significantly and consistently increased 3-methylglutaconic acid excretion, where the 3-methylglutaconic aciduria is a hallmark of the phenotype and the key to diagnosis. Until now these disorders were labelled by roman numbers (I-V) in the order of discovery regardless of pathomechanism. Especially, the so called "unspecified" 3-methylglutaconic aciduria type IV has been ever growing, leading to biochemical and clinical diagnostic confusion. Therefore, we propose the following pathomechanism based classification and a simplified diagnostic flow chart for these "inborn errors of metabolism with 3-methylglutaconic aciduria as discriminative feature". One should distinguish between "primary 3-methylglutaconic aciduria" formerly known as type I (3-methylglutaconyl-CoA hydratase deficiency, AUH defect) due to defective leucine catabolism and the--currently known--three groups of "secondary 3-methylglutaconic aciduria". The latter should be further classified and named by their defective protein or the historical name as follows: i) defective phospholipid remodelling (TAZ defect or Barth syndrome, SERAC1 defect or MEGDEL syndrome) and ii) mitochondrial membrane associated disorders (OPA3 defect or Costeff syndrome, DNAJC19 defect or DCMA syndrome, TMEM70 defect). The remaining patients with significant and consistent 3-methylglutaconic aciduria in whom the above mentioned syndromes have been excluded, should be referred to as "not otherwise specified (NOS) 3-MGA-uria" until elucidation of the underlying pathomechanism enables proper (possibly extended) classification.

Costeff optic atrophy syndrome: new clinical case and novel molecular findings.

3-Methylglutaconic aciduria (MGA) encompasses a heterogeneous group of disorders, often coinciding with elevated levels of urinary 3-methylglutaric acid. Type I MGA is a disorder of leucine metabolism, while the biological basis for the MGA is unclear for the other types (MGA types II-V). MGA type III (Costeff optic atrophy syndrome, autosomal recessive optic atrophy-3 or optic atrophy plus syndrome, OMIM 258501) is distinguished by early bilateral optic atrophy, later-onset spasticity, extrapyramidal dysfunction, ataxia, and occasional cognitive deficits. It is caused by homozygous mutations in the optic atrophy 3 gene (OPA3). We present a case of a patient with MGA who has infantile-onset optic atrophy, ataxia, extrapyramidal movements and spasticity, but with normal intellect. Sequencing of the patient's DNA revealed a homozygous nonsense mutation c.415C>T (p.Q139X) in exon 2 of transcript 2 of the OPA3 gene, as well as a common silent polymorphism c.231T>C in the same exon. This is the first nonsense mutation found in OPA3. The molecular findings in OPA3 are also reviewed, including mutations in OPA3 that result in autosomal dominant optic atrophy and cataract (ADOAC). The recessive mode of inheritance of MGA type III as a result of the p.Q139X mutation is supported by the carrier status of the unaffected father.

18Fluoro-2-deoxyglucose (18FDG) PET scan of the brain in type IV 3-methylglutaconic aciduria: clinical and MRI correlations.

The clinical, 18fluorodeoxyglucose positron emission tomography (18FDG PET) and the magnetic resonance imaging (MRI) brain scan characteristics of four patients diagnosed to have 3-methylglutaconic aciduria were reviewed retrospectively. The disease has a characteristic clinical pattern. The initial presentations were developmental delay, hypotonia, and severe failure to thrive. Later, progressive encephalopathy with rigidity and quadriparesis were observed, followed by severe dystonia and choreoathetosis. Finally, the patients became severely demented and bedridden. The 18FDG PET scans showed progressive disease, explaining the neurological status. It could be classified into three stages. Stage I: absent 18FDG uptake in the heads of the caudate, mild decreased thalamic and cerebellar metabolism. Stage II: absent uptake in the anterior half and posterior quarter of the putamina, mild-moderate decreased uptake in the cerebral cortex more prominently in the parieto-temporal lobes. Progressive decreased thalamic and cerebellar uptake. Stage III: absent uptake in the putamina and severe decreased cortical uptake consistent with brain atrophy and further decrease uptake in the cerebellum. The presence of both structural and functional changes in the brain, demonstrated by the combined use of MRI and 18FDG PET scan, with good clinical correlation, make the two techniques complementary in the imaging evaluation of 3-methylglutaconic aciduria.

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

It is generally accepted that patients with cerebral palsy suffer from a static encephalopathy causing a non-progressive disorder of posture and/or movement. We describe 7 patients from 5 families who were initially diagnosed with cerebral palsy. Eventually, excessive excretion of urinary 3-methyl glutaconic acid (3-MGA) was found. The data of our 7 patients are quite similar to the clinical description of Costeff et al (1989): Jewish-Iraqi origin (7/7), consanguinity (2/7), involuntary movements (5/7), ataxia (6/7), pyramidal involvement (6/7) and optic atrophy (6/7). The cognitive functions were intact in 5/7 and 2/7 showed mild to moderate mental retardation. The mean delay in the definitive diagnosis was 9 years. Cerebral palsy-like symptoms accompanied by optic atrophy and extrapyramidal signs should call for extensive metabolic evaluation including the determination of urinary 3-MGA.

3-Methylglutaconic aciduria in the Iraqi-Jewish 'optic atrophy plus' (Costeff) syndrome.

Eleven new patients of Iraqi-Jewish origin with bilateral optic atrophy, neurological abnormalities ('optic atrophy plus' syndrome) and 3-methylglutaconic aciduria (type III) are described. Clinical abnormalities in decreasing order of frequency were bilateral optic atrophy, extrapyramidal signs, spasticity, ataxia, dysarthria and cognitive deficit. An association with age was found only for spasticity. Spasticity, extrapyramidal signs and optic atrophy frequently led to major disability, in contrast to ataxia, dysarthria and cognitive deficit. The combined excretion of 3-methylglutaconic and 3-methylglutaric acid ranged between 9 and 187 mmol/mol creatinine. The primary enzymatic defect possibly may reside in the mitochondrial respiratory chain.

3-Methylglutaconic aciduria in "optic atrophy plus".

Behr's syndrome consists of recessively inherited infantile optic atrophy, together with chronic neurological disturbances such as ataxia, extrapyramidal dysfunction, and juvenile spastic paresis. This syndrome was found to be relatively common among Iraqi Jews. For our study, 18 such patients underwent metabolic study. All 18 showed abnormally elevated excretion of 3-methylglutaconic acid in their urine. The basic enzymatic defect is as yet unknown. We recommend that patients with early optic atrophy, and especially those with motor dysfunction, be examined for this organic aciduria.