Developmental profile and diagnoses in children presenting with motor stereotypies

Introduction: Motor stereotypies represent a typical example of the difficulty in distinguishing non-clinical behaviors (physiological and transient) from symptoms or among different disorders (“primary stereotypies”, associated with Autistic Spectrum Disorder, Intellectual Disabilities, genetic syndromes, sensory impairment). Aim of this study was to get an accurate analysis on the relationship between stereotypies and neurodevelopmental disorders. Methods: We studied 23 children (3 girls) aged 36 to 95 months, who requested a consultation due to the persistence or the increase severity of motor stereotypies. None of patients had a previous diagnosis of ASD. The assessment included the Motor Severity Stereotypy Scale (MSSS), the Repetitive Behavior Scale-Revised (RBS-R), the Raven’s Colored Progressive Matrices (CPM), the Child Behavior Checklist for ages 1 ½ -5 or 4-18 (CBCL), the Social Responsiveness Scale (SRS) and the Autism Diagnostic Observation Schedule- Second edition (ADOS 2). Results: All patients were showing motor stereotypies for periods of time varying from 6 to 77 months. The MSSS showed each child had a limited number of stereotypies; their frequency and intensity were mild; the interference of stereotypies was variable; the impairment in the daily life was mild. The RBS-R scores resulted positive for the subscale of “Stereotypic behaviors” in all children; moreover, several children presented other repetitive behaviors, mainly “Ritualistic behavior” and “Sameness behavior”. All patients showed a normal cognitive level. The CBCL evidenced behavioral problems in 22% of the children: Internalizing problems, Attention and Withdrawn were the main complaints. On the SRS, all but one of the tested patients obtained clinical scores in the clinical range at least in one area. On the ADOS 2, four patients obtained scores indicating a moderate level of ASD symptoms, four had a mild level and fifteen showed no or minimal signs of ASD. Discussion: Motor stereotypies in children with normal cognitive level represent a challenging diagnostic issue for which a finely tailored assessment is mandatory in order to define a precise developmental profile. Notably, a careful and cautious use of standardized tests is warranted to avoid misdiagnosis. Furthermore, it is hard to consider motor stereotypies, even the primary ones, exclusively as a movement disorder

Developmental motor profile in preschool children with primary stereotypic movement disorder

Aim. Different neuropsychological dysfunctions have been described in children with primary Stereotypic Movement Disorder (SMD), mainly attention or motor coordination problems. Up to now with no study has evaluated psychomotor functions in preschoolers primary SMD. The aim of this observational study was to gather information on the motor profiles of SMD patients in this age range in comparison with typically developing children. Patients and Methods. Twenty-six children (four girls) aged 36 to 76 months (mean= 53 ±10) with primary SMD were assessed by a structured evaluation including the Movement Assessment Battery for Children-Second Edition (MABC-2), the Beery-Buktenica Developmental test of Visual-Motor Integration (VMI), the Repetitive Behaviour Scale-Revised (RBS-R), the Motor Severity Stereotypy Scale (MSSS), and the Child Behaviour Checklist (CBCL). The diagnoses of Intellectual Disability or Autism Spectrum Disorder were exclusion criteria from the study. A comparison group of twenty-seven (four girls) typically developing children without stereotypies aged 36 to 59 months (mean= 48 ±7) was also examined. Results. The MABC-2 total score was lower than 15th percentile in fifteen children with SMD (58%); the worst performances were observed in Balance and Manual Dexterity subtests. The motor coordination score of VMI was lower than 15th percentile in ten children (38%). The majority of the children with low scores at MABC-2 also had low scores at the motor coordination subscale of VMI. MABC-2 standard scores of the clinical group were significantly lower than those of controls on MABC-2 Total, Balance, and Ball Skills subtests. Conclusion. The finding of widespread dysfunction of gross and fine motor abilities in preschoolers with primary SMD seems to delineate a peculiar phenotype and could provide new approaches to the management of this neurodevelopment disorder

Synthesis of “All-Cis” Trihydroxypiperidines from a Carbohydrate-Derived Ketone: Hints for the Design of New β-Gal and GCase Inhibitors

Pharmacological chaperones (PCs) are small compounds able to rescue the activity of mutated lysosomal enzymes when used at subinhibitory concentrations. Nitrogen-containing glycomimetics such as aza- or iminosugars are known to behave as PCs for lysosomal storage disorders (LSDs). As part of our research into lysosomal sphingolipidoses inhibitors and looking in particular for new β-galactosidase inhibitors, we report the synthesis of a series of alkylated azasugars with a relative “all-cis” configuration at the hydroxy/amine-substituted stereocenters. The novel compounds were synthesized from a common carbohydrate-derived piperidinone intermediate 8, through reductive amination or alkylation of the derived alcohol. In addition, the reaction of ketone 8 with several lithium acetylides allowed the stereoselective synthesis of new azasugars alkylated at C-3. The activity of the new compounds towards lysosomal β-galactosidase was negligible, showing that the presence of an alkyl chain in this position is detrimental to inhibitory activity. Interestingly, 9, 10, and 12 behave as good inhibitors of lysosomal β-glucosidase (GCase) (IC50 = 12, 6.4, and 60 µM, respectively). When tested on cell lines bearing the Gaucher mutation, they did not impart any enzyme rescue. However, altogether, the data included in this work give interesting hints for the design of novel inhibitors.España e Ministerio de Economía y Competitividad (CTQ2016-77270-R

Piperidine Azasugars Bearing Lipophilic Chains: Stereoselective Synthesis and Biological Activity as Inhibitors of Glucocerebrosidase (GCase)

We report a straightforward synthetic strategy for the preparation of trihydroxypiperidine azasugars decorated with lipophilic chains at both the nitrogen and the adjacent carbon as potential inhibitors of the lysosomal enzyme glucocerebrosidase (GCase), which is involved in Gaucher disease. The procedure relies on the preparation of C-erythrosyl N-alkylated nitrones 10 through reaction of aldehyde 8 and primary amines 13 followed by oxidation of the imines formed in situ with the methyltrioxorhenium catalyst and urea hydrogen peroxide. The addition of octylMgBr to nitrone 10e provided access to both epimeric hydroxylamines 21 and 22 with opposite configuration at the newly created stereocenter in a stereodivergent and completely stereoselective way, depending on the absence or presence of BF3·Et2O. Final reductive amination and acetonide deprotection provided compounds 14 and 15 from low-cost d-mannose in remarkable 43 and 32% overall yields, respectively, over eight steps. The C-2 R-configured bis-alkylated trihydroxypiperidine 15 was the best ligand for GCase (IC50 = 15 μM), in agreement with MD simulations that allowed us to identify the chair conformation corresponding to the best binding affinity.MINECO (CTQ2016- 77270-R) and (PID2019-104090RB-100

Exploring architectures displaying multimeric presentations of a trihydroxypiperidine iminosugar

The synthesis of new multivalent architectures based on a trihydroxypiperidine α -fucosidase inhibitor is reported herein. Tetrava- lent and nonavalent dendrimers were obtained by means of the click chemistry approach involving the copper azide-alkyne- catalyzed cycloaddition (CuAAC) between suitable scaffolds bearing terminal alkyne moieties and an azido-functionalized piperi- dine as the bioactive moiety. A preliminary biological investigation is also reported towards commercially available and human glycosidase

An Intramolecular Hydroaminomethylation-Based Approach to Pyrrolizidine Alkaloids under Microwave-Assisted Heating

A general method for the synthesis of pyrrolizidine derivatives using an intramolecular hydroaminomethylation protocol (HAM) under microwave (MW) dielectric heating is reported. Starting from a 3,4-bis(benzyloxy)-2-[(benzyloxy)methyl]-5-vinylpyrrolidine, MW-assisted intramolecular HAM in the presence of gaseous H2 and CO gave the natural alkaloid hyacinthacine A2 protected as benzyl ether. The same approach gave a lentiginosine analogue starting from the corresponding vinyl N-hydroxypyrrolidine. The nature of the reaction products and the yields were strongly influenced by the relative stereochemistry of the starting pyrrolidines, as well as by the catalyst/ligand employed. The use of ethanol as a solvent provides environmentally friendly conditions, while the ligand/catalyst system can be recovered by separating the alkaloid product with an SCX column and recycling the ethanolic solution. HAM worked up to three times with the recycled catalyst solution without any significant impact on yield

Light-triggered control of Glucocerebrosidase inhibitors: towards photoswitchable pharmacological Chaperones

Piperidine-based photoswitchable derivatives have been developed as putative pharmacological chaperones for glucocerebrosidase (GCase), the defective enzyme in Gaucher disease (GD). The structure-activity study revealed that both the iminosugar and the light-sensitive azobenzene are essential features to exert inhibitory activity towards human GCase and a system with the correct inhibition trend (IC50 of the light-activated form lower than IC50 of the dark form) was identified. Kinetic analyses showed that all compounds are non-competitive inhibitors (mixed or pure) of GCase and the enzyme allosteric site involved in the interaction was identified by means of MD simulations. A moderate activity enhancement of mutant GCase assessed in GD patients' fibroblasts (ex vivo experiments) carrying the most common mutation was recorded. This promising observation paves the way for further studies to improve the benefit of the light-to-dark thermal conversion for chaperoning activity