Congenital diseases

In Italy, every year, approximately 5% of children are born with congenital diseases , that is, pathologies that are determined during conception or during embryonic-fetal development and cause structural, functional or metabolic anomalies. To date, thousands of congenital diseases have been identified, some are evident from birth, others may be asymptomatic for several years. Congenital diseases can be caused by genetic or environmental factors or have a multifactorial cause. Congenital diseases due to genetic factors are caused by the mutation of a single gene or by anomalies in the structure or number of chromosomes. In the first case, the mutations follow the laws of Mendelian inheritance, so if the mutation concerns a dominant gene, each child, whether male or female, has a 50% chance of inheriting the disease, in this case we speak of dominant inheritance ( Marfan Syndrome, Achondroplasia ). If, on the other hand, the mutation involves a recessive gene, the disease will only occur in homozygous subjects for the recessive gene, while heterozygous children will be healthy carriers of the disease. This is called recessive heredity and the child of two healthy carriers of that mutation has a 25% chance of having the disease ( Cystic Fibrosis, Tay-Sachs Disease ). When, on the other hand, the mutation is located on the X chromosome, it is called X-linked heredity; the mother is a healthy carrier of the disease, which however will only occur in her male children, while her female children will always be healthy carriers ( Hemophilia, Duchenne Muscular Dystrophy ). Chromosomal abnormalities are the cause of various congenital diseases, including: Down syndrome , due to trisomy of chromosome 21, Turner syndrome , where the X chromosome is missing, Cri du Chat syndrome.in which subjects affected by this disease have a deletion of the short arm of chromosome 5. The environment and the substances we come into contact with every day significantly affect our lives, even embryonic-fetal development can be strongly influenced by exposure to infectious agents, chemical agents, the intake of narcotic substances, alcohol or drugs with a teratogenic action. For a woman who is planning a pregnancy or is already expecting a child, it is important to inform her doctor of all the substances she may come into contact with, both at home and at work (disinfectants, paints, organic solvents, etc.), to tell him all the drugs she is taking, all the infectious diseases she has contracted and the vaccinations she has received. It is also important for the future mother to avoid smoking and the intake of alcoholic substances. Before taking any drug, it is important to inform the doctor of the pregnancy, the sadly well-known case of Thalidomide , a drug that in the past was administered against nausea, only to later discover the serious teratogenic effects of this drug. Today, both doctors and future parents are very careful to avoid taking substances that can have negative effects on embryo-fetal development and the knowledge acquired in the field of congenital diseases allows us to inform future parents very well about the behaviors to avoid. Then, there are those congenital diseases that have a multifactorial cause, which are due to the combination of genetic and environmental factors. In this case, the child has inherited certain genes that make him more predisposed to a certain disease if there is exposure to certain substances, such as cigarette smoke. Therefore, if during prenatal life the unborn child has not come into contact with these substances, he will not have the disease; this type of congenital pathology includes: cardiac malformations, cleft palate and neural tube defects. Thanks to many diagnostic tests it is possible to diagnose a congenital disease before birth, in some cases a timely prenatal therapy can improve the life prospects of the child, for example two very serious hereditary diseases, biotin-dependence and methylmalonic aciduria, can be resolved with adequate prenatal care and the child will be born perfectly healthy. Performing all prenatal tests is very important in fact, even in cases where it is not possible to cure the disease, knowing before birth that a child suffers from a congenital disease can help the parents but also the doctor to operate in the most appropriate way.