We all hope for a healthy baby, but unfortunately it does happen sometimes that the baby has a genetic abnormality or disorder. Instantly recognizable on the outside? No, not always. In many cases, a hereditary disease or disorder will be visible through a different appearance, behavior or other malfunctioning of the body. But sometimes this is not discovered until later. In addition, a genetic abnormality may remain invisible for a long time, and is reflected when outside factors come into play with. Furthermore, there are diseases which are recessive: they can be inherited and are passed on to the offspring without ill themselves to be. It is in advance not always predict whether a baby has a genetic disorder, but prenatal testing during pregnancy can sometimes offer inconclusive.
With a genetic abnormality, disorder or condition, we mean a deviation in one or more of the genes. The genetics are the genes. These are located on the chromosomes. Genes consist of smaller pieces of DNA. A chromosome is made up of multiple pieces of thread-like strands of DNA.
Every normal body cell has 23 pairs of different chromosomes, so 46 in total. They are arranged in pairs, that is to say there are in each case two are the same. A chromosome contains many genes. Chromosome pairs one each from the mother and one from the father. Appearance are the same chromosomes in pairs, but the genes may differ. Thus, the chromosome, for example, which is derived from the father, the gene for red contain hair, while the chromosome that comes contain the gene for black hair of the mother. The dominant gene will ultimately determine the hair color, but again this varies per gene per function.
A genetic abnormality comprises a disease, disorder or condition that ensures that the baby is going to suffer from a gain, and is limited in his or her life. Having red hair for instance is not a hereditary disorder, although not every child will be happy with this color.
We know over 2,000 diseases that are related to heredity. These diseases are thus caused by an abnormal gene. Some diseases occur equally in men and women, others only in men or in women. For example, color blindness, which occurs mainly in men. Why? Because the genes for color vision to act only on the female sex hormone can be found, the X-chromosome. Girls inherit twice the X chromosome. If one of these chromosomes contain an error gene, another gene on the other chromosome will then take over, making color blindness is rare in girls. Boys have this double 'security' is not. They have one X and one Y chromosome. When the X chromosome contains the defective gene, then there is no replacement alternative. The boy is then color blind.
Genetic diseases often consist of an abnormality in the chromosomes. This may have occurred during the fusion of egg and sperm, or later in the pregnancy. It is clear that especially the first four weeks of pregnancy are decisive. Down syndrome is a common example of a chromosome abnormality. With age of the woman are increased, the risk of Down's syndrome. Which does not mean this is a congenital defect, but a deviation which is the genetic material. We distinguish between the hereditary and non-hereditary form of Down Syndrome. In many cases, it comes with a congenital defect to an excess or deficiency of chromosome pairs, or an abnormality in the chromosome itself. Gets over half a percent of all babies are affected.
In other cases, a change takes place in the genes. We know the X-linked genetic diseases: this is the cause of the female sex. We understand the autosomal abnormalities. This means that the cause is to be found on the chromosomes in cells of the body. These may be dominant as well as recessive. Dominant means that the deviation need to be on one gene, for example via a chromosome of father or mother. Recessive means that on both chromosomes is the deviation, so both of father and mother on. Only when that is the case, the deviation is expressed. In one to two percent of all newborn babies we see action this mutation.
Sometimes there are hereditary diseases or abnormalities which are partly determined by external influences. The construction of the deviation is present, but other factors play a role whether it manifests itself. Thus the environment in which we grow up will help determine whether genes undergo a change. Tobacco smoking also plays a big role. In addition, we see that food increasingly to the fore will be. During pregnancy outside factors can play a role, such as food or toxic substances ingested by the mother. So the predisposition to diabetes often determines hereditary but will get outside factors are decisive or anyone diabetes or not. For many diseases is that it is unclear to what extent heredity or environmental influences play a role and reinforce each other. Almost get four percent of all babies are affected.
Many genetic abnormalities at birth visible or noticeable. They can be detected even during pregnancy, although this does not apply to any deviations. But there are also variations that are not visible or measurable at birth. For example, the predisposition for diabetes, breast cancer or lung cancer. In these cases, external influences can help determine whether someone gets the disease at a later age. The baby thus need not visibly ill at birth. Indeed, it is highly likely that the baby with the genetic abnormality may never become ill.