The LINCE Project: A Pathway for Diagnosing NCL2 Disease.

Introduction: Neuronal Ceroid Lipofuscinosis (NCL) comprises a clinically and genetically heterogeneous group of 13 neurodegenerative lysosomal storage disorders. Neuronal Ceroid lipofuscinosis type 2 disease (NCL2), caused by the deficient lysosomal enzyme tripeptidyl peptidase 1 (TPP1), is the only one with an approved enzyme replacement treatment (ERT). Early initiation of ERT appears to modify significantly the natural history of the disease. We aimed to shorten the time to diagnosis of NCL2. Methods: In March 2017, we started per first time in Spain a selective screening program, the LINCE project, in pediatric patients with clinical symptoms compatible with NCL2 disease. The program covered the whole country. We distributed kits to pediatricians with the necessary material to assess patients. All samples in this study were received within one week of collection. Enzymatic activity determined on dried blood spots was the main method used to screen for TPP1 and palmitoyl protein thioesterase 1 (PPT1) for the differential diagnosis with neuronal ceroid lipofuscinosis type 1 (NCL1). Results: Over a period of three years, we received 71 samples. The analysis was minimally invasive, relatively cheap and fast-executing. Three cases identified as a direct result of the selective screening strategy were confirmed by genetic study of NCL2 disease with a median age of 4.5 years. Our screening method has a specificity of 100%, and, with the absence to date of false negatives. We did not detect any NCL1-positive cases. Conclusions: LINCE proved to be a simple, useful, and reliable tool for the diagnosis of NCL2, enabling clinicians to diagnose NCL2 faster. The presence of NCL2-positive cases in our population and availability of treatment may facilitate the inclusion of NCL2 in neonatal screening programs for early diagnosis.

Family study of a novel mutation of mucopolysaccharidosis type VI with a severe phenotype and good response to enzymatic replacement therapy: Case report.

RATIONALE: Mucopolysaccharidosis type VI (MPS VI) or Maroteaux-Lamy syndrome is produced by the deficiency of the enzyme arylsulfatase B, responsible for the hydrolysis of N-acetyl-D-galactosamine, chondroitin sulfate, and dermatan sulfate. PATIENT CONCERNS: A 3-year-old male with Moroccan origins is the index case. He had healthy consanguineous parents and 4 healthy brothers and sisters. The patient showed a wide spectrum of symptoms including skeletal dysplasia and short stature with elevated glycosaminoglycans (GAGs) in urine. DIAGNOSES, INTERVENTIONS, AND OUTCOMES: GAGs were quantified by spectrometry method with 1,9-dimethylen blue in 24-hour urine samples. The qualitative analysis of urine GAGs was obtained by thin-layer chromatography to determine the predominant presence of dermatan sulfate. The activities of both arylsulfatase B and beta-galactosidase as well as genetic studies were performed in dried blood spots. The genetic study was performed with deoxyribonucleic acid by massive sequencing a of lisosomal storage diseases. Results showed a new mutation c.263A > C with the severe phenotype in homozygous in the patient. The familiar study of ARSB and GLB1 genes presented some asymptomatic SNPs but with a discrete decrease in the activity of arylsulfatase B and beta-galactosidase. After an early detection by pediatricians, and both enzymatic and genetic confirmation, the patient had a good response to substitutive enzymatic treatment with galsulfase. LESSONS: Mucoplysaccharidosis type VI is an autosomal recessive rare disease characterized by a lysosomal storage disorder. Although a number of mutations have been already associated to the disease, we have found a new mutation located in the arylsulfatase B enzyme gene. We have described that this mutation is the ultimate cause of a severe presentation of the disease.

Deactivation of the coordinating ability of the iminophosphorane group by the effect of ortho-carborane.

The C-carboranyl iminophosphorane compounds derived from triphenylphosphine (I1) and o-(methylthiophenyl)-diphenylphosphine (I2) were obtained and structurally characterized. Functionalization with sulfur on the other cage carbon atom gave the corresponding disulfides (L1L1 and L2L2). In the case of I1 it was also possible to isolate the trisulfide (L1SL1) and the thiol (L1H), which is not in the expected zwitterionic form, showing that the carborane group reduces the basicity of the nitrogen atom. The disulfides were made to react with the zero-valent metal precursors [M(PPh3)4], where M = Pd, Pt. The structural analysis of the final complexes revealed the non-coordinating nature of the nitrogen atom. The isolated platinum complexes (PtL1 and PtL2) show metalation on an adjacent boron atom of the carborane cage while the palladium complexes (PdL1 and PtL2) do not complete the BH activation and are isolated as pseudo-agostic complexes. The weak pseudo-agostic interaction can be displaced by incoming ligands. Thus, reaction of PdL1 with dppm and dppe diphosphines leads to the isolation of the cis-bis(thiolates) [Pd(L1)2(dppm)] (PdL1dppm) and [Pd(L1)2(dppe)] (PdL1dppe). The non-carboranyl disulfide analogue (L3L3) was prepared and made to react with the zero-valent palladium precursor. The structure of the non-carboranyl palladium analogue (PdL3) shows the coordinating ability of the nitrogen donor atom, proving the deactivating effect of the C-carboranyl group.