Las enfermedades de depósito lisosomal: ¿por qué los pacientes consultan al reumatólogo? / Lysosomal storage diseases: why do patients consult the rheumatologist?

The lysosomal storage diseases (LSD) are a group of approximately 50 hereditary diseases affecting the activity of several enzymes that degrade macromolecules within lysosomes. As consequence, incompletely degraded substrates are accumulated, causing cell damage and progressive multisystem diseases. Although they are considered part of the so called “rare diseases”, the LSD have become relevant since the availability for several of them of a specific treatment, through the periodic infusion of recombinant forms of the deficient enzymes. This enzyme replacement therapy can significantly improve the prognosis and the quality of life of patients. Several of the LSD affect the osteoarticular system, given symptoms that lead patients to consult first to the rheumatologist. The aim of this review is to highlight the clinical aspects of LSD, giving raise to the differential diagnosis with the rheumatic diseases...

Las enfermedades de depósito lisosomal (EDL) son un grupo de aproximadamente 50 patologías hereditarias que afectan la actividad de las enzimas que degradan diversas macromoléculas dentro de los lisosomas. Como consecuencia, se acumulan sustratos incompletamente degradados, produciendo daño celular y un cuadro clínico multisistémico y progresivo. Aunque se les considera parte de las llamadas “enfermedades raras”, las EDL han adquirido relevancia, pues desde hace pocos años es posible el tratamiento específico de varias de ellas a través de la infusión periódica de formas recombinantes de las enzimas deficientes, lo que puede mejorar significativamente el pronóstico vital y la calidad de vida de los pacientes. Dado que varias de las EDL comprometen al sistema osteoarticular, no es infrecuente que los pacientes consulten en primera instancia al reumatólogo. El objetivo de esta revisión es destacar los aspectos clínicos de aquellas EDL en las que se puede plantear el diagnóstico diferencial con patologías reumatológicas...

Las mucopolisacaridosis / The mucopolysaccharidosis

Las mucopolisacaridosis (MPS) son errores innatos del metabolismo de los glicosaminoglicanos (GAG), que ocurren por déficit de alguna de las enzimas que degradan estas moléculas en los lisosomas. Esto conduce al depósito intralisosomal progresivo de GAG en diferentes tejidos, lo que explica el carácter multistémico de estas patologías. Las MPS, se presentan con una frecuencia aproximada de 1 caso en 10.000 a 25.000 recién nacidos vivos y son de herencia autosómica recesiva, salvo la MPS II o enfermedad de Hunter, que se hereda ligada al cromosoma X. Las características clínicas más frecuentes de las MPS son la presencia de rasgos faciales toscos, macrocefalia, opacidades corneales, disostosis múltiple, talla baja, valvulopatía mitroaórtica, hepatoesplenomegalia, hernias umbilical e inguinales, con o sin retraso del desarrollo sicomotor y con un deterioro neurológico progresivo. Salvo para las formas menos severas de MPS I, hasta ahora no hay un tratamiento efectivo para estas patologías, por lo que el daño sistémico progresivo produce la muerte entre los fines de la primera y de la cuarta década de la vida. En esta revisión se discuten las características clínicas de las MPS con las particularidades de cada fenotipo, el modo de confirmar el diagnóstico y los avances recientes en su tratamiento.

Fenilquetonuria de diagnóstico neonatal y lactancia materna / Phenylketonuria diagnosed during the neonatal period and breast feeding

Phenylketonuria (PKU) is due to of a defect in the phenylalanine hydroxylase gene (12q22-24.1) leading to hyperphenylalaninemia. Treatment consists in a low phenylalanine (Phe) diet. Aim: To evaluate the evolution of early diagnosed PKU children, receiving direct breast feeding, and a special formula without Phe, during their first six months of life. Patients and methods: Nineteen PKU children diagnosed in the neonatal period (19.29±13.8 days of age), treated with breast feeding and formula without Phe since diagnosis, were studied. Intake of calories, proteins and dietary Phe were quantified. Blood Phe, nutritional status and psychomotor development were also measured. Results: The diet that these children received during the 6 months period of study, had a mean of 127±19.9 Kcal/kg/day, 1.95±0.3 g protein/kg/day and 35.3±9.5 mg Phe/kg/day. Fifteen children maintained the blood level of Phe under 8 mg/dl, considered an excellent metabolic control. Only 4 cases had intermittently high levels, between 10-12 mg/dl. At 6 months of age, 74% of the children maintained breast feeding as the only source of Phe. Sixty three percent had a normal nutritional status, 5.2% were at nutritional risk and 31.6% were overweight. Eighty one percent had a normal mental development. Conclusions: The use of direct breast feeding allows a good metabolic control and improves growth and development of early diagnosed PKU children (Rev Méd Chile 2003; 131: 1280-87).

Mucolipidosis tipo II: comunicación de un caso / Mucolipidoses type II: case report

We report a female newborn with type II mucolipidoses. This condition is characterized clinically by Hurler like features, progressive psychomotor retardation and death during the first or second year of life. Most cases present during the first year of life, with poor weight gain and coarse facies features. The cause of this rare autosomal recessive hereditary disease is the deficiency of the enzyme N-acetylglucosamine-1-phosphotransferase, required for the synthesis of mannose-6-phosphate, the ligand that allows the transport of acid hydrolases into lysosomes. The patient had clinical features commonly found in mucolipidosis II, including disproportionate dwarfism, retarded psychomotor development, coarse facies features, gibbous and restricted joint mobility. The diagnosis was proved by an extremely elevated activity of lysosomal enzymes in the serum, secondary to non-regulated secretion and subsequent intracellular depletion of these proteins. The child suffered recurrent pneumonia and died at 22 months of age

Diagnóstico y seguimiento de 23 niños con acidurias orgánicas / Diagnosis and follow up of 23 children with organic acidurias

Background: Propionic aciduria (PA) and Methymalonic aciduria (MMA) result from an inherited abnormality of the enzymes propionyl CoA carboxylase and methylmalonyl CoA mutase respectively. This produces marked increases in the amino acids methionine, threonine, valine and isoleucine (MTVI). Their clinical presentation can be neonatal or late onset forms. Aim: To report 23 children with organic acidurias. Material and methods: Twenty three cases of organic acidurias diagnosed since 1980 (17 PA and 6 MMA) and followed at the Institute of Nutrition and Food Technology, are reported. Results: The average age of diagnosis was 3.9 days for the neonatal form and 8.3 months for the late onset form. The most frequent symptoms were hypotonia, lethargy and vomiting. Neonatal PA had mean ammonemias of 1089ñ678.3 µg/dl. The figure for MMA was 933ñ801.9 µg/dl. Seven children were dialyzed and 30 percent died. 16 children are followed and 81.2 percent have normal weight for age. Seven children required gastrostomy because of anorexia and failure to thrive. The nutritional treatment is based on natural and artificial proteins without MTVI, with periodical controls, amino acid and ammonia quantification. Some patients were submitted to enzyme assays and molecular studies. Conclusions: An early diagnosis and a very strict follow up allows a normal development of children with organic aciduras. There is a relationship between prognosis and the presentation form, the nutritional status and the emergency treatment during acute episodes. The importance of the enzymatic and molecular studies is emphasized because they facilitate treatment, accurate diagnosis and allow an adequate genetic counseling