Vitamin deficiencies in children: Lessons from clinical and neuroimaging findings.

BACKGROUND AND AIMS: Water-soluble vitamins play an essential coenzyme role in the nervous system. Acquired vitamin deficiencies are easily treatable, however, without treatment, they can lead to irreversible complications. This study aimed to provide clinical, laboratory parameters and neuroimaging data on vitamin deficiencies in an attempt to facilitate early diagnosis and prompt supplementation. METHODS: From July 1998 to July 2023, patients at Necker-Enfants-Malades Hospital presenting with acute neurological symptoms attributed to acquired vitamin deficiency were included. Clinical data were extracted from Dr Warehouse database. Neuroimaging, biochemical and electrophysiological data were reviewed. RESULTS: Patients with vitamin B1 deficiency exhibited abnormal eye movements (n = 4/4), fluctuations in consciousness (n = 3/4), and ataxia (n = 3/4). Brain MRI showed alterations of fourth ventricle region (n = 4/4), periaqueductal region (n = 4/4), tectum (n = 3/4), and median thalami (n = 3/4). Patients with vitamin B2 deficiency presented with early onset hypotonia (n = 3/4), hyperlactatemia (n = 4/4), and hyperammonemia (n = 4/4). Plasma acylcarnitines revealed a multiple acyl-coA dehydrogenase deficiency-like profile (n = 4/4). In vitamin B12 deficiency, young children presented with developmental delay (n = 7/7) and older children with proprioceptive ataxia (n = 3/3). Brain MRI revealed atrophy (n = 7/7) and spinal MRI hyperintensity in posterior cervical columns (n = 3/3). Metabolic findings showed elevated methylmalonic acid (n = 6/7) and hyperhomocysteinemia (n = 6/7). Patients with vitamin C deficiency exhibited gait disturbances and muscle weakness (n = 2/2). CONCLUSIONS: Acquired vitamin deficiencies may display reversible clinical symptoms mimicking inherited metabolic disorders. Some situations raise suspicion for diagnosis: concordant clinical presentation, suggestive neuroimaging findings, and/or biochemical evidence. Any acute neurological condition should be treated without waiting for definitive biochemical confirmation.

Recurrent "outsider" intronic variation in the SLC5A6 gene causes severe mixed axonal and demyelinating neuropathy, cyclic vomiting and optic atrophy in 3 families from Maghreb.

Sodium dependent multivitamin transporter (SMVT) deficiency is a very rare autosomal recessive disorder characterized by multisystemic clinical manifestations due to combined biotin, panthotenic acid and lipoic acid deficiency. About 10 families have been described so far. Accurate diagnosis is crucial because of the possibility of a supplementation treatment with proven efficacy. Here we describe 4 new patients (3 additional families) originating from the same world region (Algeria, Maghreb). All patients, born form consanguineous parents, were homozygous carriers of the same intronic variation, outside of canonical sites, in the SLC5A6 gene encoding SMVT. RNA study in one family allowed confirming the pathogenic effect of the variation and re-classifying this variant of uncertain significance as pathogenic, opening the possibility of genetic counseling and treatment. The identification of the same variation in three distinct and apparently unrelated families is suggestive of a founder effect. The phenotype of all patients was very similar, with systematic optic atrophy (initially considered as a very rare sign), severe cyclic vomiting, and rapidly progressive mixed axonal and demyelinating sensory motor neuropathy.

Treatment by oral creatine, L-arginine and L-glycine in six severely affected patients with creatine transporter defect.

BACKGROUND: X-linked cerebral creatine deficiency is caused by the deficiency of the creatine transporter (CTP) encoded by the SLC6A8 gene. PATIENTS AND METHODS: We report here a series of six patients with severe CTP deficiency, four males and two females; clinical presentations include mild to severe mental retardation (6/6), associated with psychiatric symptoms (5/6: autistic behaviour, chronic hallucinatory psychosis), seizures (2/6) and muscular symptoms (2/4 males). Diagnosis was suspected upon elevated urinary creatine/creatinine (except in one of the female patients) and on a markedly decreased creatine peak on magnetic resonance spectroscopy (MRS). Diagnosis was confirmed by molecular analysis that identified four novel mutations not reported so far, including a mutation found twice in two male patients. All patients were treated successively and according to the same protocol by creatine alone then combined to its precursors, L-glycine and L-arginine for 42 months. RESULTS AND CONCLUSION: In our patients, creatine supplementation alone or with its precursors L-glycine and L-arginine showed benefit only in the muscular symptoms of the disease and no improvement in the cognitive and psychiatric manifestations and did not modify brain creatine content on MRS of male and female CTP deficient patients. New treatment strategies are required including creatine derivatives transported independently from CTP or using alternative pathways and transporters.

Early onset collagen VI myopathies: Genetic and clinical correlations.

OBJECTIVE: Mutations in the genes encoding the extracellular matrix protein collagen VI (ColVI) cause a spectrum of disorders with variable inheritance including Ullrich congenital muscular dystrophy, Bethlem myopathy, and intermediate phenotypes. We extensively characterized, at the clinical, cellular, and molecular levels, 49 patients with onset in the first 2 years of life to investigate genotype-phenotype correlations. METHODS: Patients were classified into 3 groups: early-severe (18%), moderate-progressive (53%), and mild (29%). ColVI secretion was analyzed in patient-derived skin fibroblasts. Chain-specific transcript levels were quantified by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), and mutation identification was performed by sequencing of complementary DNA. RESULTS: ColVI secretion was altered in all fibroblast cultures studied. We identified 56 mutations, mostly novel and private. Dominant de novo mutations were detected in 61% of the cases. Importantly, mutations causing premature termination codons (PTCs) or in-frame insertions strikingly destabilized the corresponding transcripts. Homozygous PTC-causing mutations in the triple helix domains led to the most severe phenotypes (ambulation never achieved), whereas dominant de novo in-frame exon skipping and glycine missense mutations were identified in patients of the moderate-progressive group (loss of ambulation). INTERPRETATION: This work emphasizes that the diagnosis of early onset ColVI myopathies is arduous and time-consuming, and demonstrates that quantitative RT-PCR is a helpful tool for the identification of some mutation-bearing genes. Moreover, the clinical classification proposed allowed genotype-phenotype relationships to be explored, and may be useful in the design of future clinical trials.

Transient magnetic resonance diffusion abnormalities in West syndrome: the radiological expression of non-convulsive status epilepticus?

The purpose of this study was to report patients with pharmacoresistant West syndrome of unknown cause whose magnetic resonance imaging (MRI) with diffusion weighted imaging (DWI) showed a transient decrease of diffusion in subcortical structures. Of 20 patients investigated over a 2-year period, three males and three females constitute the present series. They had daily clusters of infantile spasms with hypsarrhythmia for 4 to 24 months before the first investigation. Four were severely hypotonic. All aetiological studies involving intermediary metabolism, peroxysomes, mitochondria, and neurotransmitters in cerebrospinal fluid were negative. Patients underwent DWI when first examined at the mean age of 13 months, and on follow-up examination 6 to 18 months later. Diffusion was decreased in the pallidi and posterior brainstem. It was also decreased for five patients in thalami and for three in dentate nuclei. Repeat MRI, performed when spasms were still present but hypsarrhythmia had ceased, did not show the same abnormalities. Because of recruitment bias, this series probably overestimates the true incidence of such DWI abnormalities. The eventuality of toxic lesions, including some inborn error of metabolism or drug toxicity, is considered unlikely although it could not be excluded. The contribution of the epileptic encephalopathy itself appears the most likely course.