Hypertrophic cardiomyopathy, or HCM, is an autosomal dominant genetic disorder characterized by asymmetric left ventricular hypertrophy without ventricular dilation. It is more common in men and is typically diagnosed in young, athletic adults.EtiologyHCM is primarily genetic and is caused by mutations in genes encoding sarcomeric proteins. Researchers have identified over 1400 mutations across at least 11 different genes. Among these, the most frequently occurring mutations are found in the...

Hypertrophy is the increase in the size of individual cells, resulting in the enlargement of a tissue or organ. Unlike hyperplasia, which involves an increase in cell number, hypertrophy is characterized by an increase in cell volume. This process often occurs in response to higher functional demand or hormonal stimulation, leading to the production of more structural proteins and organelles, thereby enhancing the cells' work capacity.There are two primary types of hypertrophy: physiological...

Systolic Heart Failure and Compensatory MechanismsSystolic heart failure (also termed HFrEF, Heart Failure with Reduced Ejection Fraction) is the most prevalent type of heart filure. It results in a decreased volume of blood being pumped from the ventricle. The aortic arch and carotid sinuses have baroreceptors that detect reduced blood pressure, triggering the sympathetic nervous system (SNS) to release epinephrine and norepinephrine. Initially, this response aims to boost heart rate and...

Mitral regurgitation is characterized by the backward circulation of blood from the left ventricle to the left atrium during systole, a phase of the cardiac cycle when the heart contracts and pumps blood out of the chambers. This abnormal flow occurs primarily due to the dysfunction of the mitral valve or its supporting structures, which include the mitral leaflets, chordae tendineae, annulus, and papillary muscles.Etiology and Mechanisms:Primary Mitral Regurgitation: This type arises from...

Huntington disease or HD is a progressive, fatal neurodegenerative disorder inherited in an autosomal dominant pattern.PathophysiologyIt is caused by expansion of the CAG trinucleotide repeat in the HTT gene on chromosome 4 (4p16.3), producing an abnormal huntingtin protein with an expanded polyglutamine tract. This misfolded protein disrupts cellular function, leading to neuronal death. Normal alleles have ≤26 repeats, 27–35 are intermediate (risk of expansion), 36–39 show reduced penetrance,...

Hyperplasia is an increase in the number of cells in a tissue or organ due to enhanced cell division. It is an adaptive, controlled response to stimuli such as injury, hormones, or stress, involving mitosis to produce genetically identical cells and support tissue repair and regeneration.Tissue CapacityCertain tissues, including the epidermis, intestinal epithelium, bone marrow, and fibroblasts, have a high potential for hyperplasia. Others, such as bone, cartilage, and smooth muscle, show...