INTRODUCTION Mucopolysaccharidoses (MPS), which belong to the family of inborn errors of metabolism, are characterised by their severe clinical manifestations (skeletal, neurological and visceral) and a chronic, progressive course leading to death at early stages of life.

AIM To accomplish an enzymatic diagnosis and characterise MPS within the Cuban population.

SUBJECTS AND METHODS A total of 664 patients with a clinical suspicion of some type of MPS were referred to the Institute of Neurology and Neurosurgery in Havana in order to determine a possible enzymatic deficiency and to classify the type of MPS involved in each case. Enzymatic determinations of alpha-L-iduronidasa, alpha-N-acetylglucosaminidase, beta-galactosidase, arylsulphatase B and beta-glucuronidase were performed in leukocyte homogenate for MPS I, IIIB, IVB, VI and VII, respectively, in patients, parents and controls.

RESULTS In all, 42 cases of MPS were diagnosed: MPS I (62%, n = 26), MPS VI (29%, n = 12), MPS IIIB (7%, n = 3) and MPS IVB (2%, n = 1). No patients with MPS VII were identified. The patients diagnosed with MPS were of both sexes and ages ranged between 4 months and 10 years. The specific activity of the enzymes that were studied was deficient in patients with respect to parents and controls. The percentage of activity was lower in patients compared to parents.

CONCLUSIONS These studies made it possible to evaluate the enzymatic deficiencies and to establish the diagnosis of MPS I, MPS IIIB, MPS IVB, MPS VI and MPS VII in the Cuban population.

Introducción Las mucopolisacaridosis (MPS), dentro de los errores innatos del metabolismo, se caracterizan por sus manifestaciones clínicas graves (esqueléticas, neurológicas y viscerales), con un curso crónico y progresivo, que conducen a la muerte en etapas tempranas de la vida.

Objetivo Diagnosticar enzimáticamente y caracterizar las MPS en la población cubana.

Sujetos y métodos Se remitió un total de 664 pacientes con sospecha clínica de algún tipo de MPS al Instituto de Neurología y Neurocirugía de La Habana para determinar la posible deficiencia enzimática y clasificar el tipo de MPS. Las determinaciones enzimáticas de alfa-L-iduronidasa, N-alfa-acetilglucosaminidasa, beta-galactosidasa, arilsulfatasa B y beta-glucuronidasa se realizaron en homogenado de leucocitos para MPS I, IIIB, IVB, VI y VII, respectivamente, en pacientes, padres y controles.

Resultados Se diagnosticaron 42 casos de MPS: MPS I (62%, n = 26), MPS VI (29%, n = 12), MPS IIIB (7%, n = 3) y MPS IVB (2%, n = 1). No se identificó ningún paciente con MPS VII. Los pacientes con MPS diagnosticados fueron de ambos sexos, y el rango de edad osciló de 4 meses a 10 años. La actividad específica de las enzimas estudiadas fue deficitaria en pacientes respecto a padres y controles. El porcentaje de actividad resultó inferior en pacientes respecto a padres.

Conclusión Estos estudios permitieron valorar las deficiencias enzimáticas y establecer el diagnóstico de las MPS I, IIIB, IVB, VI y VII en la población cubana.