👤 Mehmet Muhittin Yalcin

Aberrant expression of glucose-dependent insulinotropic peptide receptors (GIPR) might regulate increased steroidogenesis in patients with ACTH-independent cortisol hypersecretion. This study investigated the presence of aberrant GIPR expression in patients with ACTH-independent cortisol hypersecretion and bilateral adrenal adenomas.Patients with bilateral adrenal adenomas, ACTH-independent CS and aberrant GIPR screened via mixed meal test were included. Patients' demographic features and laboratory and imaging findings were obtained retrospectively.Twenty-one patients were included. Overt CS findings were present in 14.3% of the patients. One patient (4.7%) had a complete positive response (537% increase) and one patient (4.7%) had a partial response (41% increase) to the mixed meal test. In the remaining 19 patients, a mean change of -10.1% (range: -56.5% to+24.7%) in cortisol levels was observed at 120 min compared to baseline. The patient with a complete positive response was confirmed using 100 µg of IV octreotide. The patient underwent unilateral adrenalectomy after an inadequate long-term response to octreotide LAR therapy. The histopathology revealed bilateral macronodular adrenal cortical disease. We identified a germline heterozygous frameshift variant in the KDM1A gene in the patient's blood sample and a recurrent deletion of the p arm of chromosome 1 harboring the KDM1A locus in the adrenal sample.These results may provide useful insights into the screening of aberrant GIPR expression in patients with ACTH-independent hypercortisolism. It is essential to further investigate which patients require screening. Moreover, a significant cortisol peak observed during the mixed meal test in the presence of these receptors has drawn attention. Show less

Myosin-binding protein C 3 (MYBPC3) variants are the most common cause of hypertrophic cardiomyopathy (HCM). HCM is a complex cardiac disorder due to its significant genetic and clinical heterogeneity. MYBPC3 variants genotype-phenotype associations remain poorly understood. We investigated the impact of two novel human MYBPC3 splice-site variants: V1: c.654+2₆₅₄₊₄dupTGG targeting exon 5 using morpholino MOe5i5; and V2: c.772+1G>A targeting exon 6 using MOe6i6; located within C1 domain of cMyBP-C protein, known to be critical in regulating sarcomere structure and contractility. Zebrafish MOe5i5 and MOe6i6 morphants recapitulated typical characteristics of human HCM with cardiac phenotypes of varying severity, including reduced cardiomyocyte count, thickened ventricular myocardial wall, a drastic reduction in heart rate, stroke volume, and cardiac output. Analysis of all cardiac morphological and functional parameters demonstrated that V2 cardiac phenotype was more severe than V1. Coinjection with synthetic human MYBPC3 messenger RNA (mRNA) partially rescued disparate cardiac phenotypes in each zebrafish morphant. While human MYBPC3 mRNA partially restored the decreased heart rate in V1 morphants and displayed increased percentages of ejection fraction, fractional shortening, and area change, it failed to revert the V1 ventricular myocardial thickness. These results suggest a possible V1 impact on cardiac contractility. In contrast, attempts to rescue V2 morphants only restored the ventricular myocardial wall hypertrophy phenotype but had no significant effect on impaired heart rate, suggesting a potential V2 impact on the cardiac structure. Our study provides evidence of an association between MYBPC3 exon-specific cardiac phenotypes in the zebrafish model providing important insights into how these genetic variants contribute to HCM disease. Show less