What is Hemophilia? Hemophilia is an X-linked recessive inherited bleeding disorder caused by pathogenic variants in the F8 gene located at Xq28 or the F9 gene at Xq27 of the X chromosome, leading to impaired synthesis and function of coagulation factor VIII (FVIII) or coagulation factor IX (FIX), respectively. Clinically, it manifests as spontaneous or post-traumatic bleeding due to impaired thrombin generation. The global actual prevalence of hemophilia is approximately 17.1 per 100,000 male residents. Among these, hemophilia A (HA) caused by FVIII deficiency accounts for 80%-85%, while hemophilia B (HB) caused by FIX deficiency accounts for 15%-20%. Based on plasma coagulation factor activity levels (FVIII:C/FIX:C), it can be classified as severe (<1 IU/dL), moderate (1-5 IU/dL), or mild (5-40 IU/dL).

What is Methylmalonic Acidemia? Methylmalonic Acidemia (MMA) is an autosomal recessive inherited organic acid metabolism disorder that typically manifests in the neonatal period or early infancy. The disease has an insidious onset and rapid progression, presenting with multisystem involvement. Characteristic neurological manifestations include intellectual disability, hypotonia, basal ganglia stroke-like lesions, and hyperammonemic encephalopathy. Metabolic disturbances may present as ketosis, hyperglycinemia, and metabolic acidosis. Multiorgan involvement can affect the kidneys (chronic renal failure), vision (optic atrophy), hearing (sensorineural deafness), bones (osteoporosis, short stature), and hematopoietic system (bone marrow failure). Patients often experience concurrent liver and kidney damage. Newborn screening data indicate a birth prevalence of approximately 1/28,000.

What is Tuberous Sclerosis Complex? Tuberous Sclerosis Complex (TSC) is a rare autosomal dominant genetic disorder that primarily affects multiple organs including the brain, skin, kidneys, heart, and lungs. The typical features of TSC include cortical tubers, seizures, intellectual disability, facial angiofibromas, renal angiomyolipomas (AML), and other manifestations. With a global incidence of approximately 1/6,000 to 1/10,000, TSC represents the most common neurocutaneous syndrome.

What is Non-Syndromic Deafness? Deafness is the most common birth defect, with a global incidence of hearing loss in newborns of 1.86‰. Currently, it is widely accepted that over 60% of deafness cases are caused by genetic factors. Hereditary deafness can be classified into two types: syndromic hearing loss (SHL) and non-syndromic hearing loss (NSHL), which is the most common form of hereditary deafness, accounting for approximately 70% of all cases.

What is Duchenne Muscular Dystrophy? Duchenne Muscular Dystrophy (DMD) is a rare X-linked recessive genetic disorder primarily caused by mutations in the DMD gene, leading to the absence of dystrophin protein. This protein is crucial for maintaining the stability of muscle cell membranes.