274 Kinds Of Genetic Diseases

The main purpose of PGS / PGD is to help patients with familial genetic diseases block genetic diseases and successfully give birth to healthy babies，PGS/ PGD is based on the first and second generation IVF technology to achieve eugenics.

Now PGS Technology (detecting the chromosome number and structure of blastocysts) has been innovated in three stages:

①Fish technology – early stage: Only 5 pairs of chromosomes can be detected. The US has basically eliminated the use. Now, only domestic and Thailand are still using it.

②ACGH technology – already spread across the US. the number and structure of all 23 pairs of chromosomes in blastocyst can be screened.

③NGS technology – a new gene sequencing technology. Comprehensive screening of 23 pairs of chromosomes in blastocysts, It is accurate to small microdeletions of chromosome and with higher accuracy.

PGD technology diagnoses through gene breakthrough points, block the genetic pathogenic gene and avoid the recurrence of tragedy in future generations. At the beginning, more than a dozen genetic diseases (primary stage) to 125 diseases were screened, but now already can be screened 274 genetic diseases.

Knowledge points: PGS / PGD technology operation is to cultivate fertilized eggs to form blastocysts on the 5th day, this technology is used to detect the genes of blastocyst cells (peripheral cells that will develop into placenta in the future are extracted and made into slices), determine whether the blastocyst has chromosome abnormalities or carries genetic pathogenic genes, and then select healthy and high-quality blastocysts for transplantation, fundamentally eliminate the risk of neonatal chromosome disease or genetic disease. In other words, as long as can find the genetic breakthrough point, PGS/PGD can detect it.

PGS / PGD technology can block 274 genetic diseases，we will introduce three common and influential genetic diseases in detail in here:

1、Thalassemia

It is a genetic disease with wide distribution, large population, high incidence rate and great influence. It is also called marine anemia. The disease is mainly due to the disorder of globin chain synthesis caused by autosomal genetic defects, resulting in the insufficient or complete lack of one or more globins, resulting in hemolytic anemia in which red blood cells are dissolved and destroyed, The clinical manifestations are anemia, hepatosplenomegaly, accompanied by jaundice, dysplasia or combined with heart disease, which seriously affect the health and life safety of patients.

China is a country with high incidence of thalassemia, which is more common in the south, especially in Guangdong, Guangxi and Hainan. According to statistics, the gene carrying rate of thalassemia in Guangdong Province is as high as 16.8%, and about 1 in 9 people is affected by this genetic disease. Usually, after a thalassemia gene carrier marries a normal person, 50% of the offspring are normal and 50% are carriers. If the husband and wife are patients with the same type of thalassemia gene, 25% of their babies are moderate and severe thalassemia children, 50% are carriers, and the probability of healthy childbirth is only 1 / 4.

2、Hemophilia

Hemophilia is a hemorrhagic disease caused by hereditary coagulation dysfunction. Due to the obstacle of active thromboplastin production and the prolongation of coagulation time, hemophilia has the tendency of slight post-traumatic bleeding all his life, Even without obvious trauma, severe patients can have “spontaneous bleeding,” which is life-threatening at any time.

Hemophilia is divided into three categories: A, B and C, Hemophilia A and hemophilia B is a sex linked recessive genetic disease, that is, it belongs to sex X chromosome linked recessive genetic disease and is only transmitted with X. it has the characteristics of “female transmission and male onset”

(Note: when the male is present with the disease gene, the incidence rate is 100%. When two sex X chromosomes contain pathogenic genes, only a pathogenic gene is a carrier)

Based on this, if both husband and wife are hemophiliacs, the children are also hemophiliacs, but if the woman is normal, the man is hemophilia, the son will be normal, and the daughter is the carrier; If the woman is a carrier and the man is normal. The hemophilia probability of a son is 50%, and the probability of a daughter become a carrier is 50%.

3、Spinal Muscular Atrophy

It is a kind of disease caused by degeneration of motor neurons in the anterior horn of the spinal cord, which leads to muscle weakness and muscle atrophy. It is an autosomal recessive disease, It is not uncommon in clinic and can be called a terminal disease more cruel than cancer. It is mainly caused by the injury of upper motor neurons and lower motor neurons, resulting in the gradual weakness and atrophy of trunk, limbs, chest and abdominal muscles, resulting in respiratory failure. Scientist Stephen Hawking is suffering from this genetic disease. The incidence rate is 1/6000~1/10000, and the probability of having a child with spinal muscular atrophy is 25%, 50% of them are carriers, and the probability of having a healthy child is 25%.

In addition, there are hydrocephalus syndrome, mental retardation syndrome, deaf thyroid syndrome, congenital Finnish nephropathy, retinitis pigmentosa and other common genetic diseases.

At present, there is no complete medical treatment for genetic diseases. The effective way is to avoid them through the American gene screening and diagnosis technology PGS/PGD. Select healthy blastocysts for transplantation, which avoids the possibility of disease in the next generation.