ABSTRACT
Congenital myasthenic syndromes are a group of genetically determined rare diseases resulting from ultrastructural alterations in synaptic proteins. Up to 32 genes are known to be involved in those syndromes and many mutations have been reported, of which less than 8% affect the presynaptic complex. One of these syndromes is caused by the impairment of the presynaptic sodium-dependent high-affinity choline transporter 1, as a result of a mutation of the SCL5A7 gene associated with congenital myasthenic syndrome type 20 (MIM # 617143). We present a new case of this syndrome, caused by a mutation not previously described. A full term infant presented with acute respiratory failure and generalized weakness. The genetic analysis revealed the patient to be compound heterozygous for a new mutation of the SCL5A7 gene. The genetic analysis of congenital myasthenic syndromes provide information on the ultrastructural underlying mechanisms, which is valuable for differential diagnosis and specific treatments.
Subject(s)
Mutation , Myasthenic Syndromes, Congenital/genetics , Symporters/genetics , Diagnosis, Differential , Humans , Infant, Newborn , Male , Muscle Weakness/diagnosis , Muscle Weakness/genetics , Muscle Weakness/physiopathology , Muscle Weakness/therapy , Myasthenic Syndromes, Congenital/diagnosis , Myasthenic Syndromes, Congenital/physiopathology , Myasthenic Syndromes, Congenital/therapy , Phenotype , Respiratory Insufficiency/diagnosis , Respiratory Insufficiency/genetics , Respiratory Insufficiency/physiopathology , Respiratory Insufficiency/therapyABSTRACT
La fibrosis quística (FQ) es una enfermedad exocrina autosómica recesiva de afectación multisistémica. El defecto asociado a la FQ se encuentra en un regulador transmembrana que actúa principalmente como canal de cloro. Los pacientes suelen presentar clínica respiratoria o digestiva. La severidad de la enfermedades multifactorial, y uno de sus determinantes es el nivel de actividad de la proteína CTFR y el tipo de mutación del paciente. El paciente de este caso desarrolló episodios recurrentes de anorexia, pérdida de peso, deshidratación y anomalías hidroelectrolíticas. A pesar de estas manifestaciones poco descritas en la bibliografía, se llegó al diagnóstico de FQ. Se encontraron las mutaciones R334W y 1812-1G-4. La FQ se debe considerar particularmente en los lactantes que presentan la clínica descrita de deshidrataciones recurrentes con alcalosis metabólica, hiponatremia e hipocloremia inexplicada por otras causas, incluso en ausencia de síntomas respiratorios, digestivos o fallo de medro(AU)
Cystic fibrosis (CF) is an autosomal recessive exocrine disease affecting multiple organ systems. The defect associated with CF is in the cystic fibrosis transmembrane regulator (CFTR), which acts primarily as a chloride channel. Patients with CF usually present with respiratory and/or gastrointestinal abnormalities. The severity of the disease is multifactorial, one of the factors depends on the level of activity of the CFTR protein, which is related with the mutation type that affects the patient. An infant is presented who developed recurrent episodes of anorexia, weight loss, dehydration and electrolyte abnormalities. CF was diagnosed showing an unusual and not very publicized presentation of the disease. Mutations R334W and 1812-1G-A were found. CF should be considered in patients of any age, but particularly in infants, presenting with recurrent episodes of hyponatremic hypochloremic dehydration with metabolic alkalosis unexplained by other causes, even in the absence of respiratory or gastrointestinal symptoms or failure to thrive(AU)
