RESUMEN
Rare de novo mutations represent a significant cause of idiopathic developmental delay (DD). The use of next-generation sequencing (NGS) has boosted the identification of de novo mutations in an increasing number of novel genes. Here we present 3 unrelated children with de novo loss-of-function (LoF) mutations in QRICH1, diagnosed through trio-based exome sequencing. QRICH1 encodes the glutamine-rich protein 1, which contains 1 caspase activation recruitment domain and is likely to be involved in apoptosis and inflammation. All 3 children had speech delay, learning difficulties, a prominent nose and a thin upper lip. In addition, 2 of them had mildly raised creatine kinase (CK) and 1 of them had autism. Despite their small number, the patients had a relatively consistent pattern of clinical features suggesting the presence of a QRICH1-associated phenotype. LoF mutations in QRICH1 are suggested as a novel cause of DD.
Asunto(s)
Trastorno Autístico/genética , Discapacidades del Desarrollo/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Proteínas de Microtúbulos/genética , Trastorno Autístico/patología , Niño , Preescolar , Creatina Quinasa , Discapacidades del Desarrollo/fisiopatología , Exoma/genética , Femenino , Predisposición Genética a la Enfermedad , Humanos , Lactante , Recién Nacido , Mutación con Pérdida de Función , Masculino , Mutación , FenotipoRESUMEN
Autism is a severe childhood disorder already presenting in the first 3 years of life and, therefore, strongly correlated with neurodevelopmental alterations in prenatal, as well as postnatal period. Neurotransmitters hold a pivotal role in development by providing the stimulation needed for synapses and neuronal networks to be formed during the critical period of neuroplasticity. Aberrations of the serotonergic system modify key processes in the developing brain and are strongly implicated in the pathophysiology of developmental disorders. Evidence for the role of serotonin in autism emerges from neuropathological, imaging and genetic studies. Due to its developmental arrest, autism requires early intervention that would, among others, target the disrupted serotonergic system and utilize brain plasticity to elicit clinically important brain changes in children.
RESUMEN
Tyrosine hydroxylase (TH) deficiency is a rare autosomal recessive disorder mapped to chromosome 11p15.5. Its clinical expression varies with presentations as dopa-responsive dystonia (recessive Segawa's disease), dopa-responsive infantile parkinsonism, dopa-responsive spastic paraplegia, progressive infantile encephalopathy or dopa-non-responsive dystonia. We describe a 7-year-old boy with progressive infantile encephalopathy and non-responsiveness to dopamine. The patient demonstrated generalized hypotonia, pyramidal tract dysfunction and temperature instability after the second month of life. Dystonia, tremor and oculogyric crises complicated the clinical picture during the following months. Neurotransmitter analysis in CSF disclosed almost undetectable levels of HVA and MHPG, whereas serum prolactin was profoundly increased. Subsequent molecular analysis revealed homozygosity for a missense mutation (c.707T>C) in the TH gene. l-Dopa therapy in both high and low doses resulted in massive hyperkinesias, while substitution with selegiline exerted only a mild beneficial effect. Today, at the age of 7 years, the patient demonstrates severe developmental retardation with marked trunkal hypotonia, hypokinesia and occasionally dystonic and/or hyperkinetic crises. He is the third Greek patient with TH deficiency to be reported. Since all three patients carry the same pathogenetic mutation, a founder effect is suspected.
Asunto(s)
Tirosina 3-Monooxigenasa/deficiencia , Estudios de Casos y Controles , Catecolaminas/biosíntesis , Niño , Preescolar , Humanos , Lactante , MasculinoRESUMEN
Autosomal dominant episodic ataxia type 2 (EA2) results from mutations of the CACNA1A gene. We describe EA2 with unusual features in a father and daughter with a novel CACNA1A mutation coding for Y248C. Both patients showed severe cerebellar atrophy in MRI and clinical signs of progressive spinocerebellar atrophy type 6. Most disabling were the very frequent episodes of ataxia with migraine (with aura in the father and without aura in the daughter) and nystagmus in our patients. Additionally, they suffered from ictal hyperhidrosis with acute hypothermia of the extremities. Lastly, the father presented with interictal chronic diarrhea not associated to a known primary gastrointestinal disorder. Both ictal hyperhidrosis and interictal diarrhea ameliorated upon acetazolamide intake, the typical treatment for EA2. The significance of these findings is discussed and the phenotype correlated to previously reported cases.
Asunto(s)
Canales de Calcio/genética , Diarrea/fisiopatología , Hiperhidrosis/fisiopatología , Hipotermia/fisiopatología , Mutación , Ataxias Espinocerebelosas/genética , Adulto , Niño , Análisis Mutacional de ADN , Diarrea/genética , Femenino , Humanos , Hiperhidrosis/genética , Hipotermia/genética , Imagen por Resonancia Magnética , Masculino , Ataxias Espinocerebelosas/diagnóstico , Ataxias Espinocerebelosas/patología , Ataxias Espinocerebelosas/fisiopatologíaRESUMEN
We present clinical, magnetic resonance imaging and MR spectroscopic findings of a female patient, first admitted at the age of 9 months for regression of motor milestones and signs of mild spastic diplegia. Magnetic resonance imaging (MRI) demonstrated periventricular white matter abnormalities with sparing of the subcortical white matter. Subsequent MRIs, performed at the ages of 13 and 16 months, demonstrated progression of the white matter changes, progressive white matter rarefaction and cystic degeneration, and additional involvement of the corpus callosum; only the subcortical white matter remained spared. Proton MR spectroscopy revealed lactate elevation in the white matter. Blood lactate and lactate/pyruvate ratio were mildly elevated. Subsequent analysis of mitochondrial function in muscle tissue showed decreases in substrate oxidation and in ATP and CrP production rates. Complex I activity was seriously decreased, whereas mild decreases of complex II and IV activities were also noted. Analysis of the NDUFV1 gene revealed compound heterozygosity for two point mutations, each of them carried by one parent. The further clinical course of the patient was uphill; she slowly regained all previously lost motor milestones. In conclusion, diffuse white matter changes on MRI are compatible with mitochondrial encephalopathy and not necessarily associated with a severe clinical course.
Asunto(s)
Encefalopatías Metabólicas/diagnóstico , Enfermedades Mitocondriales/diagnóstico , Mutación , NADH Deshidrogenasa/genética , Encefalopatías Metabólicas/genética , Encefalopatías Metabólicas/metabolismo , Niño , Complejo I de Transporte de Electrón/deficiencia , Complejo I de Transporte de Electrón/genética , Femenino , Heterocigoto , Humanos , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética/métodos , Enfermedades Mitocondriales/genética , Enfermedades Mitocondriales/metabolismo , NADH Deshidrogenasa/deficienciaRESUMEN
L-2-Hydroxyglutaric aciduria (L-2-HGA) is an autosomal recessive neurometabolic disorder characterized by psychomotor delay, ataxia, macrocephaly and typical neuroradiological findings of subcortical leucoencephalopathy. Recently, the disease causing gene has been discovered (L2HGDH) encoding L-2-hydroxyglutarate dehydrogenase. We present a 3-year-old boy with L-2-HGA, who demonstrated macrocephaly, noted already in utero with ultrasound. Cranial MRI demonstrated diffuse subcortical encephalopathy with increased signal of the subcortical white matter. Subsequent metabolic screening revealed increased levels of L-2-HGA, and genomic DNA analysis demonstrated two missense mutations in L-2-HGDG. Patient's further motor development was mildly impaired, whilst his speech development was profoundly impaired (first words at the age of 2 years). Since the age of 2 years he started demonstrating autistic repetitive behaviors and movements, increasing aloofness to his environment and limitations in the variety of spontaneous activity (CARS score: 44/60-severe autism). Autism has not so far been described in L-2-HGA and may be considered as an additional feature of the phenotypic spectrum.