Tratamiento con hormona de crecimiento en 2 pacientes con deleción 22q11.21 / Growth hormone treatment in 2 patients with 22q11.21 deletion syndrome

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[Efficiency and good tolerance of rituximab for idiopathic thrombocytopenic purpura revealing a 22q11 deletion syndrome]. / Efficacité et bonne tolérance du rituximab sur un purpura thrombopénique immunologique chronique révélant un syndrome de délétion 22q11.

INTRODUCTION: 22q11 deletion is a common genetic disorder which associates a polymalformative syndrome to dysimmune features. Autoimmunity and immune deficiency manifestations are often associated, resulting in a therapeutic challenge for this disease. CASE REPORT: We report a 28-year-old patient who presented with hemorrhagic manifestations leading to the diagnosis of severe thrombocytopenia (15,000/mm3), of both central and peripheral origin. Patient history, cardio-facial malformative syndrome, hypoparathyroidism and partial immune deficiency led to the molecular diagnosis of 22q11 deletion syndrome. After failure of polyvalent immunoglobulin infusions, rituximab alone allowed the increase of platelets to their usual level of 100-120,000/mm3 within 4 weeks and a complete clinical remission of the hemorrhagic syndrome, without any infectious complication after a 4-year follow-up. CONCLUSION: Rituximab may be an alternative to corticosteroid for the treatment of auto-immune manifestations associated with minor forms of 22q11 deletion syndrome without significant worsening of the immune deficiency.

White matter microstructural abnormalities of the cingulum bundle in youths with 22q11.2 deletion syndrome: associations with medication, neuropsychological function, and prodromal symptoms of psychosis.

BACKGROUND: The 22q11.2 deletion syndrome (22q11.2DS) is regarded as an etiologically homogenous model for understanding neuroanatomic disruptions associated with a high risk for schizophrenia. This study utilized diffusion tensor imaging (DTI) to analyze white matter microstructure in individuals with 22q11.2DS. We focused on the cingulum bundle (CB), previously shown to be disrupted in patients with schizophrenia and associated with symptoms of psychosis. METHODS: White matter microstructure was assessed in the anterior, superior, and posterior CB using the tractography algorithm in DTIStudio. Neuropsychological function, presence of prodromal symptoms of psychosis, and medication history were assessed in all participants. RESULTS: Relative to controls, young adults with 22q11.2DS showed alterations in most DTI metrics of the CB. Alterations were associated with positive prodromal symptoms of psychosis. However, when individuals with 22q11.2DS were divided by usage of antipsychotics/mood stabilizers, the medicated and non-medicated groups differed significantly in axial diffusivity of the anterior CB and in fractional anisotropy of the superior CB. DTI metrics did not differ between the medicated group and the control group. CONCLUSIONS: Results suggest that the microstructure of the CB is altered in individuals with 22q11.2DS, and that those alterations may underlie positive prodromal symptoms of psychosis. Our findings further provide preliminary evidence that antipsychotic/mood stabilizer usage may have a reparative effect on white matter microstructure in prodromal 22q11.2DS, independent of the potential effects of psychosis. Future studies of white matter pathology in individuals with 22q11.2DS should test for potential effects of medication on white matter microstructure.

Specific disruption of thalamic inputs to the auditory cortex in schizophrenia models.

Auditory hallucinations in schizophrenia are alleviated by antipsychotic agents that inhibit D2 dopamine receptors (Drd2s). The defective neural circuits and mechanisms of their sensitivity to antipsychotics are unknown. We identified a specific disruption of synaptic transmission at thalamocortical glutamatergic projections in the auditory cortex in murine models of schizophrenia-associated 22q11 deletion syndrome (22q11DS). This deficit is caused by an aberrant elevation of Drd2 in the thalamus, which renders 22q11DS thalamocortical projections sensitive to antipsychotics and causes a deficient acoustic startle response similar to that observed in schizophrenic patients. Haploinsufficiency of the microRNA-processing gene Dgcr8 is responsible for the Drd2 elevation and hypersensitivity of auditory thalamocortical projections to antipsychotics. This suggests that Dgcr8-microRNA-Drd2-dependent thalamocortical disruption is a pathogenic event underlying schizophrenia-associated psychosis.