What are the causes of congenital foot deformities?

Congenital foot deformity is a condition in which the foot is deformed due to genetic factors. Because the foot is an important part of the human body, if the foot is deformed, it will affect the patient's normal walking and bring many inconveniences to the patient's life. Generally speaking, congenital foot deformities are caused by genetic factors, environmental factors, and some other teratogenic factors, such as smoking, alcoholism, malnutrition, etc.

1. Genetic factors and congenital malformations

Congenital malformations caused by genetic factors, including chromosomal aberrations and gene mutations, account for 25% of congenital malformations. Chromosomal aberrations include abnormalities in chromosome number or chromosome structure. Chromosomes are originally opposite to each other in pairs, and a reduction in their number can cause congenital malformations, the most common of which is the monosomy. Monosomal embryos with plant chromosomes can hardly survive, and only 3% of monosomal embryos with sex chromosomes survive, but they may have deformities, such as congenital ovarian dysgenesis, namely Turner syndrome (45, 0X). An increase in the number of chromosomes can also cause deformities, which is more common in trisomy. For example, the common congenital idiocy is caused by chromosome 21. Sex chromosome trisomy (47, XXY) can cause congenital testicular dysgenesis. Structural abnormalities of chromosomes can also cause deformities. For example, the deletion of the end of the short arm of chromosome 5 can cause "cat cry syndrome." In addition to causing a few deformities, such as achondroplasia, polycystic kidney disease, and polydactyly, gene mutations mainly cause metabolic genetic diseases.

2. Environmental factors and congenital malformations

Environmental factors that can cause congenital malformations are collectively called teratogens, accounting for 10% of congenital malformations. There are three aspects of the environment that affect embryonic development, namely the external environment around the mother, the internal environment of the mother, and the microenvironment around the embryo. Some teratogens in the external environment can directly act on the embryo by changing the internal environment and microenvironment, while others can indirectly act on the embryo by changing the internal environment and microenvironment. The main environmental teratogens are biological, physical, chemical, and drug.

The physical teratogens that have been confirmed so far include: radiation, mechanical compression and injury, high temperature, etc.; industrial "three wastes", pesticides, food additives and preservatives contain some teratogenic chemicals, including certain polycyclic aromatic hydrocarbons, certain nitroso compounds, certain alkyl and benzene compounds, the pesticide diquat, lead, arsenic, cadmium, mercury, etc. The sedative "Thalidomide", which caused a large number of limb deformities in Western Europe in the 1960s, is an example of a chemical drug causing teratogenesis.

3. Other teratogenic factors

Other teratogenic factors include alcoholism, heavy smoking, hypoxia, malnutrition, etc.

Viral infection is the main type of intrauterine infection. Due to the barrier function of the placenta, some large molecular substances are generally not easy to pass through the placenta, while viruses with smaller molecular weights and some parasites can infect the embryo or fetus through the placenta. The mother is infected with various pathogenic microorganisms during pregnancy, and the diseases are transmitted to the fetus through the mother, which can cause various malformations in the fetus. The following viruses have been confirmed to have teratogenic effects on human embryos: rubella virus and cytomegalovirus.