Congenital disorder of glycosylation 1J (CDG1J) [MIM:608093]: A form of congenital disorder of glycosylation, a multisystem disorder caused by a defect in glycoprotein biosynthesis and characterized by under-glycosylated serum glycoproteins. Congenital disorders of glycosylation result in a wide variety of clinical features, such as defects in the nervous system development, psychomotor retardation, dysmorphic features, hypotonia, coagulation disorders, and immunodeficiency. The broad spectrum of features reflects the critical role of N-glycoproteins during embryonic development, differentiation, and maintenance of cell functions. Note=The disease is caused by mutations affecting the gene represented in this entry.
Myasthenic syndrome, congenital, 13 (CMS13) [MIM:614750]: A form of congenital myasthenic syndrome, a group of disorders characterized by failure of neuromuscular transmission, including pre-synaptic, synaptic, and post-synaptic disorders that are not of autoimmune origin. Clinical features are easy fatigability and muscle weakness. CMS13 is characterized by muscle weakness mostly affecting proximal limb muscles, minimal involvement of facial, ocular and bulbar muscles, and tubular aggregates present on muscle biopsy. Symptoms include difficulty walking and frequent falls. Younger patients show hypotonia and poor head control. Neurophysiological features indicate a disorder of neuromuscular transmission on electromyography. Note=The disease is caused by mutations affecting the gene represented in this entry.