Fanconi Anemia (FA) is a rare inherited bone marrow failure syndrome, primarily inherited in an autosomal recessive pattern, with approximately 2% being X-linked recessive. The disease is characterized by congenital developmental abnormalities, progressive bone marrow failure, and significantly increased susceptibility to malignancies. Clinical manifestations include café-au-lait spots (55%), short stature (51%), limb defects (43%), craniofacial abnormalities (26%), ocular abnormalities (23%), and renal anomalies.

Congenital Adrenal Hyperplasia (CAH) is a group of autosomal recessive genetic disorders caused by defects in key enzymes involved in adrenal corticosteroid synthesis. The core feature is impaired cortisol synthesis, which through negative feedback mechanisms leads to compensatory increased secretion of adrenocorticotropic hormone (ACTH), stimulating adrenal cortical hyperplasia while causing abnormal accumulation of precursor substances such as androgens.

What is Retinitis Pigmentosa? Retinitis Pigmentosa (RP) is a genetically heterogeneous retinal degenerative disorder characterized pathologically by progressive photoreceptor cell death and retinal pigment epithelium (RPE) atrophy. Common clinical manifestations include night blindness, progressive visual field constriction, and gradual loss of central vision. Typical fundoscopic findings reveal bone spicule-like pigment deposits, generalized attenuation of retinal vessels, and waxy pallor of the optic disc, constituting the classic "triad." Research indicates that RP pathogenesis is closely associated with multiple gene mutations and protein metabolism abnormalities. Based on inheritance patterns, RP is classified into three main types: autosomal dominant (adRP, accounting for approximately 15%–25%), autosomal recessive (arRP, approximately 5%–20%), and X-linked (XLRP, approximately 10%–15%).

What is Niemann-Pick Disease? Niemann-Pick Disease (NPD) is an autosomal recessive inherited lysosomal storage disorder, also known as sphingomyelin-cholesterol lipidosis. Based on pathogenesis and clinical manifestations, NPD is primarily classified into two major categories: A/B type and C type.

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).