Journal of Inborn Errors of Metabolism and Screening (Aug 2018)

Diagnosis and Management of Classical Homocystinuria in Brazil

  • Soraia Poloni PhD,
  • Giovana W. Hoss MD,
  • Fernanda Sperb-Ludwig PhD,
  • Taciane Borsatto PhD,
  • Maria Juliana R. Doriqui MD,
  • Emília K.E.A Leão PhD,
  • Ney Boa-Sorte PhD,
  • Charles M. Lourenço PhD,
  • Chong A. Kim PhD,
  • Carolina F. M. de Souza PhD,
  • Helio Rocha MD,
  • Marcia Ribeiro PhD,
  • Carlos E. Steiner PhD,
  • Carolina A. Moreno PhD,
  • Pricila Bernardi MD,
  • Eugenia Valadares PhD,
  • Osvaldo Artigalas MD,
  • Gerson Carvalho MD,
  • Hector Y. C. Wanderley MD,
  • Vânia D’Almeida PhD,
  • Luiz C. Santana-da-Silva PhD,
  • Henk J. Blom PhD,
  • Ida V. D. Schwartz PhD

DOI
https://doi.org/10.1177/2326409818788900
Journal volume & issue
Vol. 6

Abstract

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This study described a broad clinical characterization of classical homocystinuria (HCU) in Brazil. This was a cross-sectional, observational study including clinical and biochemical data from 72 patients (60 families) from Brazil (South, n = 13; Southeast, n = 37; Northeast, n = 8; North, n = 1; and Midwest, n = 1). Parental consanguinity was reported in 42% of families. Ocular manifestations were the earliest detected symptom (53% of cases), the main reason for diagnostic suspicion (63% of cases), and the most prevalent manifestation at diagnosis (67% of cases). Pyridoxine responsiveness was observed in 14% of patients. Only 22% of nonresponsive patients on treatment had total homocysteine levels <100 µmol/L. Most commonly used treatment strategies were pyridoxine (93% of patients), folic acid (90%), betaine (74%), vitamin B12 (27%), and low-methionine diet + metabolic formula (17%). Most patients diagnosed with HCU in Brazil are late diagnosed, express a severe phenotype, and poor metabolic control. Milder forms of HCU are likely underrepresented due to underdiagnosis.