What Is Familial Hypercholesterolemia? Familial Hypercholesterolemia (FH) is the most common autosomal dominant genetic disorder, triggered by pathogenic variants in genes including LDLR, APOB, PCSK9 and LDLRAP1. Its hallmark clinical manifestation is drastically elevated low-density lipoprotein cholesterol (LDL-C). Without timely…

What Is Sickle Cell Disease? Sickle Cell Disease (SCD) is an autosomal recessive disorder characterized by structural abnormalities in hemoglobin molecules. The core pathogenic driver is a point mutation in the HBB gene encoding hemoglobin β-globin. Under hypoxic conditions, mutant…

What Is Spinocerebellar Ataxia? Spinocerebellar Ataxia (SCA) refers to a heterogeneous group of inherited neurodegenerative disorders triggered by distinct pathogenic gene mutations. Many SCA subtypes are classified as dynamic repeat expansion diseases, predominantly driven by expanded CAG trinucleotide repeats. Core…

What Is Progressive Familial Intrahepatic Cholestasis? Progressive Familial Intrahepatic Cholestasis (PFIC) is a group of autosomal recessive hereditary liver disorders caused by pathogenic gene variants. Mutations disrupt hepatocyte bile formation and excretion, which may eventually progress to liver failure. Three…

What Is Ornithine Transcarbamylase Deficiency? Ornithine Transcarbamylase Deficiency (OTCD), also known as type II hyperammonemia, is an X-linked inherited metabolic disorder caused by loss or impaired activity of ornithine transcarbamylase (OTC) due to pathogenic variants in the OTC gene. It…

What Is Tyrosinemia? Hereditary tyrosinemia refers to a group of inherited metabolic disorders caused by enzymatic defects in the tyrosine degradation pathway. Based on distinct deficient enzymes, three major clinical subtypes are recognized: Type I (HT1), Type II (TAT deficiency)…

What Is Retinoblastoma? Retinoblastoma (RB) is the most common intraocular malignant tumor in children. Its pathogenesis is primarily triggered by biallic inactivation of the RB1 tumor suppressor gene; a small subset of RB cases with wild-type RB1 are driven by…

What Is Neuroblastoma? Neuroblastoma (NB) is the most common extracranial solid tumor in children, accounting for 8%–10% of all pediatric malignancies, and is known as the “king of childhood tumors” due to its highly heterogeneous clinical manifestations. Based on molecular…

What Is Fanconi Anemia? Fanconi Anemia (FA) is a rare inherited bone marrow failure syndrome. Its primary inheritance mode is autosomal recessive, while approximately 2% of cases show X-linked recessive transmission. The disease is characterized by congenital developmental abnormalities, progressive…

What Is Retinitis Pigmentosa? Retinitis Pigmentosa (RP) is a highly genetically heterogeneous degenerative retinal disorder pathologically characterized progressive photoreceptor loss and retinal pigment epithelium (RPE) atrophy. Core clinical manifestations include nyctalopia, gradual peripheral visual field constriction, and progressive central vision…