Dados do Trabalho

Título

LEUCINOSIS: THE URGENCY OF NEONATAL SCREENING TESTS FOR EARLY DIAGNOSIS

Apresentação dos casos

CASE 1: School-age, female, 9 years old, firstborn, daughter of non-consanguineous parents. Admitted to the hospital at 6 months of age due to drowsiness, bulging fontanelle, and nystagmus associated with delayed motor neurodevelopment (generalized hypotonia). Initial basic endocrine-metabolic investigation was performed without alterations. Cranial MRI showed alteration in the usual process of myelination, diffusely suggestive of Leucinosis. Tests for inborn errors of metabolism were collected, concluding the diagnosis and starting a specific and restricted diet. Over the years, she presented 2 episodes of neurological exacerbation with hypoactivity and nystagmus due to poor adherence to diet therapy.
CASE 2: Preschooler, male, 4 years old, brother of CASE 1, also diagnosed with Leucinosis after 1 year of life due to maternal complaint of urine odor similar to his sister's, but without neurodevelopmental delay. Since then, he started a specific diet and formula. Over the 4 years of his life, he had 4 episodes of decompensation also due to poor adherence to the diet. Both cases were diagnosed only after the onset of symptoms, through complex laboratory tests and imaging in tertiary/quaternary healthcare services.

Discussão

Both cases are Leucinosis, also known as maple syrup urine disease. It is an inborn error of metabolism (branched-chain ketoaciduria) caused by a deficiency in the branched-chain alpha-keto acid dehydrogenase complex. Patients have elevated plasma concentrations of leucine, isoleucine, and valine, as well as their corresponding keto acids. Such accumulations interfere with the immune, musculoskeletal, and primarily neurological systems. If the patient does not follow a specific and restricted diet, they will experience neurological exacerbations throughout their life, with potentially irreversible damage.

Comentários finais

Despite being a rare disease, Leucinosis was included in the expansion of the newborn screening test by Law No. 14,154 of May 26, 2021. However, there is still inequality and delay in the introduction of this expanded test in the country. Thus, early diagnosis and, consequently, the start of treatment to prevent damage to the patient is hindered.

Referências

Quental S, Vilarinho L, Martins E, et al. Incidence of maple syrup urine disease in Portugal. Mol Genet Metab 2010; 100:385.
Morton DH, Strauss KA, Robinson DL, et al. Diagnosis and treatment of maple syrup disease: a study of 36 patients. Pediatrics 2002; 109:999.
Puffenberger EG. Genetic heritage of the Old Order Mennonites of southeastern Pennsylvania. Am J Med Genet C Semin Med Genet 2003; 121C:18.
Zhang B, Zhao Y, Harris RA, Crabb DW. Molecular defects in the E1 alpha subunit of the branched-chain alpha-ketoacid dehydrogenase complex that cause maple syrup urine disease. Mol Biol Med 1991; 8:39.

Palavras Chave

LEUCINOSE; maple syrup disease; MSUD