What Is Angelman Syndrome? Angelman Syndrome (AS) is a neurodevelopmental disorder triggered by dysfunction of the maternally inherited UBE3A gene located on chromosomal region 15q11–13. Its hallmark clinical manifestations include severe developmental delay, intellectual disability, persistent happy demeanor, speech impairment,…

What Is Rett Syndrome? Rett Syndrome (RTT) is a severe neurodevelopmental disorder caused by loss-of-function variants in the MECP2 gene located on the X chromosome, predominantly affecting female patients. Clinical manifestations typically emerge between 6 and 18 months of age…

What Is Fibrodysplasia Ossificans Progressiva? Fibrodysplasia Ossificans Progressiva (FOP), also known as “Stone Man Syndrome”, is an ultra-rare hereditary connective tissue disorder. Its hallmark clinical features include congenital bilateral great toe malformation, together with progressive, widespread and irreversible heterotopic ossification…

What Is Paroxysmal Nocturnal Hemoglobinuria? Paroxysmal Nocturnal Hemoglobinuria (PNH) is a rare acquired clonal disorder of hematopoietic stem cells. Its classic clinical triad consists of three core manifestations: Most PNH patients die from thrombosis or progressive cytopenia. The disease incidence…

What Is Marfan Syndrome? Marfan Syndrome (MFS) is an autosomal dominant connective tissue disorder that affects multiple organ systems, primarily the skeletal, ocular, and cardiovascular systems. Typical clinical manifestations include arachnodactyly, scoliosis, lens dislocation, high myopia, and the most life-threatening…

What Is Mucopolysaccharidosis? Mucopolysaccharidosis (MPS) refers to a group of rare hereditary lysosomal storage diseases, triggered by deficiencies of specific enzymes responsible for degrading glycosaminoglycans (GAGs), also known as acid mucopolysaccharides. MPS damages multiple bodily systems, with core manifestations including…

What Is Glycogen Storage Disease (Type I & Type II)? Glycogen Storage Disease (GSD) is a rare autosomal recessive metabolic disorder triggered by deficiencies in enzymes involved in glycogen synthesis or breakdown, resulting in abnormal glycogen accumulation in the liver,…

What Is Neuromyelitis Optica Spectrum Disorder? Neuromyelitis Optica Spectrum Disorder (NMOSD) is a rare autoimmune disease targeting the central nervous system (CNS). Its hallmark clinical manifestations include recurrent optic neuritis and longitudinally extensive transverse myelitis, which frequently lead to severe…

What Is Fabry Disease? Fabry Disease (FD) is a rare X-linked lysosomal storage disorder caused by pathogenic variants in the GLA gene, which triggers a wide spectrum of clinical manifestations. The global incidence of Fabry Disease is approximately 1 in…

What Is Hepatolenticular Degeneration? Hepatolenticular Degeneration, also known as Wilson Disease (WD), is a rare autosomal recessive genetic disorder caused by mutations in the ATP7B gene, which leads to abnormal copper accumulation in organs including the liver, brain and cornea.…