What is a cleft lip? What causes a cleft lip?

For pregnant mothers, the health of their babies is their top concern. Cleft lip is something that every pregnant mother does not want to see. So what causes cleft lip? Is it hereditary?

What is a cleft lip?

Cleft lip is a common congenital malformation of the oral and maxillofacial region, with an incidence of about 1:1000. In a normal fetus, the face is formed by the gradual fusion of some embryonic protrusions after the fifth week. If these protrusions fail to develop normally, deformities may occur, including cleft lip.

Is cleft lip hereditary?

Hello, regarding the question of whether cleft lip and palate will be inherited, it is pointed out that cleft lip and palate is an autosomal recessive inheritance. It is not possible to show deformity in every generation. Only when the apparently healthy parents carry the pathogenic gene, then 1/4 of their children will have cleft lip and palate, 1/2 of the children will be healthy on the surface but actually carry the pathogenic gene of cleft lip and palate, and only 1/4 of the children will be healthy. The occurrence of cleft lip and palate at the same time among siblings is 2% to 4%. If one of the parents carries the pathogenic gene of cleft lip and palate and the other is healthy, the next generation of children will not have cleft lip and palate, but 1/2 of the children will carry the pathogenic gene. If one of the parents has a cleft lip and palate and the other is healthy, half of the next generation of children will have cleft lip and palate deformity and the other half will carry the pathogenic gene. If both parents are cleft lip and palate patients, the next generation of children will all suffer from cleft lip and palate. There are slightly more males than females in cleft lip and palate, and the male-female ratio is about 1.5:1. This is what we found after studying whether cleft lip and palate will be inherited. It can be seen that cleft lip and palate has a genetic gene, but not all people will inherit it. It's just that the next generation has a greater chance of having cleft lip and palate than the average person.

Causes of cleft lip

There are many reasons for cleft lip, the following factors are more common:

1. Genetic factors: Most children with cleft lip can be found in their direct relatives or collateral relatives with the same deformity. According to surveys, the incidence of cleft lip is 0.17%. If one parent has a cleft lip, the incidence of their children can be as high as 2.6%-5.6%, which is 15-32 times higher than the former. If the father has cleft lip and palate, the incidence of offspring is about 3%. If the mother is sick, the probability of inheriting it to the children is as high as 14%. If healthy parents have given birth to a child with cleft lip, then the probability of a second child with cleft lip is 4%. If two children with cleft lip have been born, the probability of giving birth to a child with cleft lip again rises to 9%. The incidence is even higher among children of close relatives.

2. Nutritional factors: Vomiting and picky eating during pregnancy can affect nutritional intake and cause vitamin deficiency. In animal experiments, when pregnant mice are fed food lacking vitamins A and E, the pups are often born with cleft lip and palate.

3. Viral infection: In the early stages of pregnancy (within 2 months), if the baby is infected with the rubella virus, it may be the cause of cleft lip and palate in the baby.

4. Drug factors: Some drugs can pass through the placental barrier and affect embryonic development. For example, sleeping pills, antiallergic drugs, phenytoin, corticosteroids, and cyclophosphamide can all cause fetal malformations.

5. Endocrine effects: Experiments have shown that pregnant mice injected with adrenal cortex hormones on the 9th, 10th and 11th days after pregnancy have more cleft lip and palate in their offspring. Therefore, in the early stages of pregnancy (within 8 weeks), if the pregnant woman is stressed or injured, the secretion of adrenal cortex hormones in the body may increase, leading to congenital malformations in the baby.

6. Radiation: Exposure to radiation in early pregnancy may cause cleft lip and cleft palate in the fetus.