Rare diseases, especially in children, can be a distressing affair. The search for the cause of the disease is often particularly lengthy and costly and exhausting. How high is the detection rate of rare diseases? What are the relatively common rare diseases in children in China and how long does it take to find the cause by traditional methods? Which diseases are missed due to delays in treatment?
The definition of rare diseases is not uniform, some professional associations define it as one in 10,000, some professional associations define it as one in a million, and the current more recognized definition of rare diseases is one in 10,000; although the incidence of rare diseases is low, there are many kinds of diseases, plus the large population base in China, so the total number of rare diseases is very, very large, and rare diseases that are rare worldwide will be reported in large numbers in China, such as phenylketonuria. The incidence rate is 1 in 17,000, and we have accumulated 3,000 confirmed cases in Xinhua Hospital, which is a very large number.
Currently, the rare diseases that are more recognized in China mainly focus on diagnosable and preventable diseases, such as phenylketonuria, adrenocortical hyperplasia, metabolic diseases, chromosomal microdeletion/microduplication syndrome, etc. Traditional diagnostic methods include karyotype analysis, which requires cell culture, and the diagnostic cycle is usually 2-3 weeks. Although biochemical testing is necessary, biochemical testing changes with the human body and has a large variability, which requires several follow-up dynamic observations to confirm the diagnosis, which can easily lead to delayed treatment of some diseases, such as phenylketonuria, if early treatment and early intervention can be completely unaffected by intelligence, but the diagnostic idea of phenylketonuria is three steps: 1. 1, is not phenylketonuria; 2, is classical phenylketonuria or malignant phenylketonuria; 3, genetic confirmation; sometimes biochemical results are not typical, resulting in the first step and the second step to confirm the diagnosis of difficulty, phenylketonuria has 6 genes, the first step and the second step typing leads to difficult to choose which gene to test, the subsequent diagnosis can not be carried out thus delaying treatment, but with the development of second-generation sequencing However, with the development of second-generation sequencing, we can test all 6 genes together and skip the first and second steps directly, and confirm the diagnosis by biochemical verification in the first and second steps.
What is the current status of diagnosis and treatment of rare diseases in China?
At present, rare diseases mainly rely on clinical experience and genetic diagnosis, but many rare diseases still have no treatment, and the diagnosis of such untreatable rare diseases is mainly for the prenatal diagnosis of the next child, while many rare disease genotypes can clearly guide the clinical phenotype; in addition, the diagnosis of a large number of rare disease patients will accelerate the research knowledge of drug companies and research groups on such diseases, thus laying the foundation for possible treatment.