A retrospective study on the clinical and molecular outcomes of calpainopathy in a Turkish patient cohort.

Background and aim: Calpainopathy, also known as limb-girdle muscular dystrophy recessive type 1, is a progressive muscle disorder that impacts the muscles around the hips and shoulders. The disease is caused by defects in the CAPN3 gene and can be inherited in both recessive and dominant forms. In this retrospective study, we aimed to evaluate the clinical and molecular results of our patients with calpainopathy and to examine the CAPN3 variants in Turkish and global populations. Materials and methods: Molecular analyses were performed using the next-generation sequencing (NGS) method. CAPN3 variants were identified through the examination of various databases. Results: In this retrospective study, the cohort consisted of seven patients exhibiting the CAPN3 (NM_000070.3) mutation and a phenotype compatible with calpainopathy at a single center in Türkiye. All patients displayed high CK levels and muscle weakness. We report a novel missense c.2437G>A variant that causes the autosomal dominant form of calpainopathy. Interestingly, the muscle biopsy report for the patient with the novel mutation indicated sarcoglycan deficiency. Molecular findings for the remaining individuals in the cohort included a compound heterozygous variant (frameshift and missense), one homozygous nonsense, one homozygous intronic deletion, and three homozygous missense variants. The most common variant in the Turkish population was c.550del. In both populations, pathogenic variants were most frequently located in exon 21, according to exon length. Variants were stochastically distributed based on consequences in CAPN3 domains. Conclusion: Therefore, the NGS method proves highly effective in diagnosing rare diseases characterized by clinical heterogeneity. Assessing variants based on ethnicity holds significance in the development of precise therapies.

A Case of Short Stature Caused by a Mutation in the ACAN Gene.

Introduction: Aggrecanopathies are rare disorders associated with idiopathic short stature. They are caused by pathogenic changes in the ACAN gene located on chromosome 15q26. In this study, we present a case of short stature caused by mutations in the ACAN gene. Case Presentation: A 3-year-3-month-old male patient was referred to us because of his short stature. Physical examination revealed proportional short stature, frontal bossing, macrocephaly, midface hypoplasia, ptosis in the right eye, and wide toes. When the patient was 6 years and 3 months old, his bone age was compatible with 7 years of age. The patient underwent clinical exome sequencing and a heterozygous nonsense c.1243G>T, p.(Glu415*) pathogenic variant was detected in the ACAN gene. The same variant was found in his phenotypically similar father. Our patient is the second case with ptosis. Discussion: ACAN gene mutation should be considered in the differential diagnosis of patients with idiopathic short stature. The development and widespread use of next-generation sequencing technology has increased the diagnostic and treatment possibilities.

Myasthenia gravis with acute respiratory failure in the emergency department.

Acute respiratory failure (ARF) is defined as a sudden malfunction in the ability of respiratory system to maintain adequate gas exchange. Acute hypercapnic respiratory failure develops as a result of ventilation deficiency and it is defined as an increase of PaCO2 above 45 mmHg. Myasthenia Gravis (MG) is a sporadically developing auto-immune deficiency where the neuro-muscular transmission is affected and it is one of the important reasons for neurologically-induced respiratory distress. Here, we report a case of a 75-year-old male patient previously undiagnosed MG, who presented with ARF. MG is not a common entity that we encounter daily. Patients on occasions may present to the emergency department because of acute exacerbation. Though most of them were known cases, we should be aware of some unrecognized cases and should consider MG as a differential diagnosis for patients with acute respiratory failure.