Clinical Overview Congenital Insensitivity to Pain with Anhidrosis (CIPA), also classified as Type IV Hereditary Autonomic and Sensory Neuropathy, is a rare autosomal recessive neurodegenerative disorder. It is characterized by…
Second Impact Syndrome (SIS) is a rare but potentially catastrophic condition characterized by rapid, severe cerebral swelling following a second head impact—occurring before full clinical recovery from an initial concussion.…
Clinical Overview Encephalitis lethargica (EL) is a rare, potentially devastating neuroinflammatory syndrome characterized by an acute or subacute onset of febrile illness followed by profound alterations in consciousness, sleep-wake cycles,…
Introduction Chlamydia pneumoniae is an obligate intracellular Gram-negative bacterium that is a significant cause of respiratory tract infections worldwide. First isolated in 1983 by T. Brunham and colleagues, C. pneumoniae…
Adult-onset Still’s disease (AOSD) is a rare, systemic inflammatory disorder characterized by a constellation of systemic and musculoskeletal manifestations. First described by George Still in 1897 as a childhood illness…
Overview and Epidemiology Familial Mediterranean Fever (FMF) is a rare, autosomal recessive autoinflammatory disorder characterized by recurrent episodes of fever and inflammation. It primarily affects individuals of Mediterranean and Middle…
Sunflower syndrome is a rare and distinctive form of generalized epilepsy characterized by highly stereotyped seizure activity that is uniquely triggered by exposure to bright light and accompanied by a…
Introduction Graft-versus-host disease (GVHD) is a life-threatening complication of allogeneic hematopoietic stem cell transplantation (HSCT) and certain solid organ transplants, characterized by an immunological attack of donor-derived immune cells against…
Overview and Pathophysiology Onychomycosis, or tinea unguium, is a chronic fungal infection of the nail unit characterized by significant morbidity, including pain, secondary bacterial infection, and psychosocial distress. While often…
Clinical Overview Cornelia de Lange Syndrome (CdLS) is a complex multi-systemic neurodevelopmental disorder characterized by significant intellectual disability, distinctive facial dysmorphism, growth retardation, and limb anomalies. It is primarily caused…
Physiology of Sweating Sweating—or perspiration—is a vital autonomic thermoregulatory function mediated primarily by eccrine sweat glands distributed across the skin. These glands are innervated by sympathetic cholinergic fibers, which release…
Pathophysiology and Molecular Genetics Krabbe disease is a severe, autosomal recessive lysosomal storage disorder caused by mutations in the GALCGALC gene (located on chromosome 14q31), which encodes the lysosomal enzyme…
Introduction and Pathophysiology Nutcracker syndrome (NCS), formally termed left renal vein entrapment syndrome, is a vascular disorder characterized by extrinsic compression of the left renal vein (LRV) between the abdominal…
Overview Myoclonic Epilepsy with Ragged-Red Fibers (MERRF) is a rare, progressive, multisystem mitochondrial disorder primarily affecting the central and peripheral nervous systems and skeletal muscle. First described by Davies et…
Updated with Current Evidence (2023–2024 Guidelines and Landmark Studies) 1. Introduction and Pathophysiology Diamond-Blackfan Anemia (DBA; OMIM #105650) is a rare, inherited bone marrow failure syndrome (IBMFS) characterized by a…
