Newborn Screening for Homocystinuria Revealed a High Frequency of MAT I/III Deficiency in Iberian Peninsula

Acessível em: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4375120/Homocystinuria due to cystathionine β-synthase deficiency or "classical homocystinuria" is a rare autosomal recessive condition resulting in altered sulfur metabolism with elevated methionine and homocysteine in plasma and homocystine in urine. This condition is characterized by a high clinical heterogeneity, which contributes to late clinical diagnosis, usually only made after irreversible damage has occurred. Treatment is effective if started before clinical symptoms. The analysis of methionine levels by tandem mass spectrometry (MS/MS) allows the newborn screening for homocystinuria, but false-positive results can be frequently obtained and lead to the unwanted identification of methionine adenosyl transferase (MAT I/III) deficiency. This latter condition is biochemically characterized by isolated persistent hypermethioninemia, accompanied in some individuals with slightly elevated levels of homocysteine in plasma. A dominant form of MAT I/III deficiency, associated with mutation p.R264H, seems to be very frequent in the Iberian Peninsula and usually has a clinically benign course. Both these metabolic disorders are screened in Galicia and Portugal since the introduction of the MS/MS technology, in 2000 and 2004, respectively, resulting in the identification of three patients with classical homocystinuria and 44 patients with MAT I/III deficiency. All but one heterozygous parent of MAT I/III patients, identified with the p.R264H mutation, are healthy adults around the age of 30/40. The implementation of a second-tier test for homocysteine in dried blood spots would considerably reduce the number of MAT I/III-deficient patients identified and improve the specificity and positive predictive value for classical homocystinuria screening

Spinal involvement in mucopolysaccharidosis IVA (Morquio-Brailsford or Morquio A syndrome): presentation, diagnosis and management.

Mucopolysaccharidosis IVA (MPS IVA), also known as Morquio-Brailsford or Morquio A syndrome, is a lysosomal storage disorder caused by a deficiency of the enzyme N-acetyl-galactosamine-6-sulphate sulphatase (GALNS). MPS IVA is multisystemic but manifests primarily as a progressive skeletal dysplasia. Spinal involvement is a major cause of morbidity and mortality in MPS IVA. Early diagnosis and timely treatment of problems involving the spine are critical in preventing or arresting neurological deterioration and loss of function. This review details the spinal manifestations of MPS IVA and describes the tools used to diagnose and monitor spinal involvement. The relative utility of radiography, computed tomography (CT) and magnetic resonance imaging (MRI) for the evaluation of cervical spine instability, stenosis, and cord compression is discussed. Surgical interventions, anaesthetic considerations, and the use of neurophysiological monitoring during procedures performed under general anaesthesia are reviewed. Recommendations for regular radiological imaging and neurologic assessments are presented, and the need for a more standardized approach for evaluating and managing spinal involvement in MPS IVA is addressed

Galsulfase (Naglazyme®) therapy in infants with mucopolysaccharidosis VI

OBJECTIVE: To evaluate the efficacy and safety of two dose levels of galsulfase (Naglazyme®) in infants with MPS VI. STUDY DESIGN: This was a phase 4, multicenter, multinational, open-label, two-dose level study. Subjects were randomized 1:1 to receive weekly infusions of 1.0 or 2.0 mg/kg of galsulfase for a minimum of 52 weeks. Progression of skeletal dysplasia was determined by monitoring physical appearance, radiographic changes, and growth. Urinary glycosaminoglycan (GAG) levels, gross and fine motor function, cardiac function, vision, hearing, and health resource utilization were evaluated. Safety assessments were performed. RESULTS: Four infants (aged 3.3–12.7 months) participated in the study. Galsulfase was well tolerated at 1.0 and 2.0 mg/kg/week dose levels with no drug-related serious adverse events. Two subjects experienced a total of four possible treatment-related adverse events which were all considered mild. Length and weight remained within age-expected norms. Skeletal abnormalities continued to progress in all subjects. High baseline urinary GAG levels (mean: 870 μg/mg creatinine) decreased by approximately 70 %; these reduced levels were maintained (mean: 220 μg/mg creatinine at week 52) despite the development of anti-galsulfase antibodies. Hearing, cardiac function, hepatosplenomegaly, and facial dysmorphism stabilized or improved, but corneal clouding progressed. There was no clear difference in safety or efficacy between the two doses. CONCLUSIONS: Galsulfase at two dose levels was safe and well tolerated in infants. Normal growth was maintained but skeletal abnormalities continued to progress. Urinary GAG levels decreased with treatment. Early initiation of galsulfase may prevent or slow progression of some disease manifestations. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10545-013-9654-7) contains supplementary material, which is available to authorized users