Congenital Myasthenic Syndrome associated with acetylcholine receptor deficiency: case report and review of the literature.

INTRODUCTION: Congenital Myasthenic Syndromes are a diverse group of conditions with a broad array of genetic underpinnings and phenotypic presentations. Acetylcholine receptor deficiency is one form that usually involves pathogenic variants in the Cholinergic Receptor Nicotinic Epsilon Subunit (CHRNE) gene encoding the ɛ-subunit of the acetylcholine receptor. METHODS: We report a case of a 4-year-old male with suspected Congenital Myasthenic Syndrome with Acetylcholine Receptor Deficiency who presented with ocular symptoms and generalized muscle weakness. We additionally summarize published findings regarding the genetic, phenotypic, and clinical considerations of Congenital Myasthenic Syndrome with Acetylcholine Receptor Deficiency. RESULTS: Exome sequencing revealed biallelic variants in CHRNE gene with a pathogenic frameshift variant and a variant of uncertain significance. After suboptimal response to pyridostigmine and albuterol, the patient experienced benefit with 3,4-DAP. The most commonly reported clinical characteristics in the literature are ptosis, muscle fatigability or weakness, and ophthalmoplegia. CONCLUSION: We present the case of a patient with biallelic variants in CHRNE gene including a variant of uncertain significance. Evaluation of variants of this gene, including the variant of uncertain significance identified in this case report, through further cases and studies may improve our understanding of Congenital Myasthenic Syndrome with Acetylcholine Receptor deficiency.

Co-occurring Usher syndrome Type 1 and Renal Failure.

PURPOSE: To describe a patient with a rare co-occurrence of Usher syndrome type 1C (USH1C) and renal disease, suspected to be secondary to Alport syndrome. METHOD: Case report and literature review of cases with Usher syndrome and renal failure. Clinical examination, color fundus photography, visual field tests, electroretinography and whole exome sequencing were used to diagnose and document the patient's clinical presentation. RESULTS: An 18-year-old female with known history of congenital hearing loss and chronic renal failure, presents with progressive night and peripheral visual impairment suspicious for an inherited retinal disease. Visual field testing, fundus exam and electroretinography findings supported the diagnosis of Usher syndrome. Whole exome sequencing (WES) identified a novel homozygous frameshift variant (c.238del) in USH1C. WES also identified a homozygous COL4A3 variant of unknown significance, which may be responsible for concomitant Alport syndrome. CONCLUSION: By presenting this rare case of co-occurring Usher syndrome Type 1 and renal failure, we highlight the importance of conducting further investigations that could reveal an additional underlying etiology when these entities are present.