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Título

CASE REPORT OF METABOLIC SYNDROME: THIAMINE METABOLISM DYSFUNCTION SYNDROME 2 IN AN INFANT

Apresentação do caso único

Female, born via cesarean at 39+2 weeks, APGAR 9/10. Neonatal screening showed altered TLI of 94.2. At 4 months, she developed inconsolable crying, yellow diarrhea, regurgitation, decreased food intake and chewing automatism. One month later, she presented hypotonia, "vacant gaze" and low-grade fever (37.8ºC).In emergency, she had two seizures with rhythmic jerks in all limbs. Started on phenobarbital (FNB), she had another 6-minute seizure. EEG showed left temporal interictal epileptiform activity, slowed background, disorganized rhythms and increased beta modulation. MRI indicated hyperintense areas in cortical-subcortical regions of all lobes except insulae, mainly in temporo-parietal areas, basal ganglia, thalami, midbrain, pons and cerebellum. Genetic testing confirmed Thiamine Metabolism Dysfunction Syndrome 2, responsive to thiamine and/or biotin. Treatment with Biotin and Thiamine was initiated, in addition to anticonvulsants. After three months, a respiratory infection occurred with decompensation of the epilepsy. Medication adjustments were made with a change in the pattern of the crises. Chromosomal microarray analysis did not detect pathogenic gains or losses. At 6 months, despite anticonvulsants and nasal midazolam, she had over three seizures daily. A new EEG showed persistent disorganized baseline activity with generalized irregular spike bursts in bilateral frontal areas. There was an increase in crises, requiring adjustment of anti-seizure drugs. She remained hospitalized until 10 months for seizure control.

Discussão

TMDS2 is an autosomal recessive disorder with a defect in the biotin transporter at the blood-brain barrier. It typically presents with recurrent encephalopathies starting between ages 3 and 10, often with dystonia.The infant showed an early-onset form with atypical infantile spasms, poor feeding, vomiting, acute encephalopathy and severe lactic acidosis within the first 3 months. Diagnosis is confirmed by biallelic pathogenic variants in SLC19A3 gene.Treatment includes lifelong biotin and thiamine supplementation, along with antiepileptic medication and rehabilitation.

Comentários finais

Although rare, TMDS2 should be considered in pediatric patients with recurrent seizures and progressive neurological signs. Early diagnosis through genetic testing is crucial for the appropriate treatment with thiamine and biotin, which can significantly improve prognosis and quality of life, as well as individualized management with antiepileptics.

Referências

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Palavras Chave

metabolic syndrome; thiamine metabolism dysfunction syndrome 2; epileptic seizures