RESUMEN
BACKGROUND: Adult-onset spinal muscular atrophy (SMA) represents an expanding group of inherited neurodegenerative disorders in clinical practice. OBJECTIVE: This review aims to synthesize the main clinical, genetic, radiological, biochemical, and neurophysiological aspects related to the classical and recently described forms of proximal SMA. METHODS: The authors performed a non-systematic critical review summarizing adult-onset proximal SMA presentations. RESULTS: Previously limited to cases of SMN1-related SMA type 4 (adult form), this group has now more than 15 different clinical conditions that have in common the symmetrical and progressive compromise of lower motor neurons starting in adulthood or elderly stage. New clinical and genetic subtypes of adult-onset proximal SMA have been recognized and are currently target of wide neuroradiological, pathological, and genetic studies. CONCLUSIONS: This new complex group of rare disorders typically present with lower motor neuron disease in association with other neurological or systemic signs of impairment, which are relatively specific and typical for each genetic subtype.
Asunto(s)
Enfermedad de la Neurona Motora , Atrofia Muscular Espinal , Radiología , Adulto , Humanos , Atrofia Muscular Espinal/genética , Neurofisiología , Enfermedades RarasRESUMEN
Abstract Background: Adult-onset spinal muscular atrophy (SMA) represents an expanding group of inherited neurodegenerative disorders in clinical practice. Objective: This review aims to synthesize the main clinical, genetic, radiological, biochemical, and neurophysiological aspects related to the classical and recently described forms of proximal SMA. Methods: The authors performed a non-systematic critical review summarizing adult-onset proximal SMA presentations. Results: Previously limited to cases of SMN1-related SMA type 4 (adult form), this group has now more than 15 different clinical conditions that have in common the symmetrical and progressive compromise of lower motor neurons starting in adulthood or elderly stage. New clinical and genetic subtypes of adult-onset proximal SMA have been recognized and are currently target of wide neuroradiological, pathological, and genetic studies. Conclusions: This new complex group of rare disorders typically present with lower motor neuron disease in association with other neurological or systemic signs of impairment, which are relatively specific and typical for each genetic subtype.
RESUMO Antecedentes: Atrofia muscular espinhal (AME) de início no adulto representa um grupo de doenças neurodegenerativas hereditárias em expansão na prática clínica. Objetivo: Este artigo de revisão sintetiza os principais aspectos clínicos, genéticos, radiológicos, bioquímicos e neurofisiológicos relacionados às formas clássicas e recentemente descritas de AME proximal do adulto. Métodos: Os autores realizaram uma revisão crítica não sistemática descrevendo as principais apresentações de AME proximal de início no adulto. Resultados: Previamente restrito às apresentações de AME tipo 4 associada ao gene SMN1, este grupo atualmente envolve mais de 15 diferentes condições clínicas que compartilham entre si a presença de comprometimento progressivo e simétrico do neurônio motor inferior se iniciando no adulto ou no idoso. Novos subtipos clínicos e genéticos de AME proximal de início no adulto foram reconhecidas e são alvos atuais de estudos direcionados a aspectos neurorradiológicos, patológicos e genéticos. Conclusões: Este novo grupo complexo de doenças raras tipicamente se apresenta com doença do neurônio motor inferior em associação com outros sinais de comprometimento neurológico ou sistêmico, os quais apresentam padrões relativamente específicos para cada subtipo genético.
Asunto(s)
Humanos , Radiología , Atrofia Muscular Espinal/genética , Enfermedad de la Neurona Motora , Enfermedades Raras , NeurofisiologíaRESUMEN
Adult polyglucosan body disease (APBD) represents a complex autosomal recessive inherited neurometabolic disorder due to homozygous or compound heterozygous pathogenic variants in GBE1 gene, resulting in deficiency of glycogen-branching enzyme and secondary storage of glycogen in the form of polyglucosan bodies, involving the skeletal muscle, diaphragm, peripheral nerve (including autonomic fibers), brain white matter, spinal cord, nerve roots, cerebellum, brainstem and to a lesser extent heart, lung, kidney, and liver cells. The diversity of new clinical presentations regarding neuromuscular involvement is astonishing and transformed APBD in a key differential diagnosis of completely different clinical conditions, including axonal and demyelinating sensorimotor polyneuropathy, progressive spastic paraparesis, motor neuronopathy presentations, autonomic disturbances, leukodystrophies or even pure myopathic involvement with limb-girdle pattern of weakness. This review article aims to summarize the main clinical, biochemical, genetic, and diagnostic aspects regarding APBD with special focus on neuromuscular presentations.
Asunto(s)
Sistema de la Enzima Desramificadora del Glucógeno/genética , Enfermedad del Almacenamiento de Glucógeno/genética , Enfermedad del Almacenamiento de Glucógeno/fisiopatología , Enfermedades del Sistema Nervioso/genética , Enfermedades del Sistema Nervioso/fisiopatología , Adulto , Encéfalo/patología , Enfermedad del Almacenamiento de Glucógeno/patología , Humanos , Músculo Esquelético/patología , Enfermedades del Sistema Nervioso/patología , Nervios Periféricos/patología , Fenotipo , Médula Espinal/patologíaRESUMEN
BACKGROUND: Hypomyelinating leukodystrophies represent an expanding group of neurogenetic disorders characterized primarily by central nervous system hypomyelination and variable neurological and non-neurological involvement. Hypomyelinating disorders have been rarely associated with gonadal dysfunction, being mainly represented by hypogonadotrophic hypogonadism in 4H syndrome. WT1 gene-associated disorders are classically associated with complex phenotypes including early carcinogenic risk for gonadoblastoma and Wilms' tumor, chronic renal failure, nephrotic syndrome and sex developmental disorders in intersex disorders and ambiguous genitalia. METHODS: The authors describe three non-related Brazilian patients with hypomyelinating leukodystrophy associated with complex neurological and systemic dysfunction with WT1 gene mutations. RESULTS: All described patients presented with similar neuroimaging features including thin corpus callosum, mild to moderate cerebellar atrophy and diffuse periventricular and profound hypomyelinating leukodystrophy involving supratentorial white matter with classical compromise linked to inherited non-somatic WT1 gene mutations in a similar pattern to Denys-Drash syndrome, including nephrotic syndrome with different glomerular disease, chronic renal failure, intersex disorder with ambiguous genitalia, and early occurrence of specific tumors, such as Wilms' tumor and gonadoblastoma. CONCLUSIONS: Clinicians must include WT1 gene mutations in the differential diagnosis of hypomyelinating leukodystrophy with nephrotic syndrome, chronic renal failure, ambiguous genitalia or sex developmental disorders.
