What is Fibrodysplasia Ossificans Progressiva? Fibrodysplasia Ossificans Progressiva (FOP), often referred to as "Stone Man Syndrome," is an extremely rare genetic disorder. It is characterized by congenital bilateral great toe malformations and progressive, widespread, irreversible heterotopic ossification (HO) of soft tissues throughout the body, ultimately leading to severe disability. The incidence is approximately 1 in 1 million.

What is Rett Syndrome? Rett Syndrome (RTT) is a severe neurological disorder primarily affecting females, caused by mutations in the Methyl-CpG binding protein 2 (MECP2) gene located on the X chromosome. Symptoms typically begin to manifest between 6 and 18 months of age. Following a brief period of normal development after birth, patients undergo a developmental regression, characterized by loss of acquired language and hand skills, development of stereotypic hand movements, gait abnormalities, breathing irregularities (apnea, hyperventilation), scoliosis, anxiety, and sleep disturbances. The incidence of RTT is approximately 1 in 10,000 to 1 in 15,000 live female births.

What is Angelman Syndrome? Angelman Syndrome (AS), also known as Angelman syndrome, is a neurodevelopmental disorder caused by abnormalities in the maternal allele of the UBE3A gene located in the 15q11-13 chromosomal region. Its main characteristics include severe developmental delay, intellectual disability, a happy demeanor with frequent laughter, language impairment, ataxia, and seizures. The incidence of AS is approximately 1 in 20,000 to 1 in 12,000.

What is Phenylketonuria? Phenylketonuria (PKU) is a common monogenic inherited disorder, classified as an autosomal recessive genetic condition. It is caused by mutations in the phenylalanine hydroxylase (PAH) gene, leading to congenital metabolic dysfunction that prevents normal metabolism of phenylalanine (Phe), resulting in its accumulation in the blood and organs. PKU patients typically exhibit severe developmental delay, neurological deficits, behavioral abnormalities, and epileptic seizures. In China, the overall incidence of PKU is approximately 1 in 11,000, with higher prevalence in northern populations compared to southern regions.

Pulmonary Alveolar Proteinosis (PAP) is a rare disease characterized by abnormal accumulation of surfactant material within the alveoli, primarily classified into acquired (autoimmune), congenital, and secondary types. Among these, autoimmune PAP (also known as idiopathic or adult-onset PAP) is the most common, accounting for approximately 90% of all cases. The typical clinical presentation includes insidiously progressive dyspnea, which may be accompanied by dry cough or scanty frothy sputum. Imaging often reveals diffuse "crazy-paving" or ground-glass opacities. Epidemiological data indicate that the prevalence of this disease is approximately 6.87 cases per million population.