GENETICIST ASSOCIATED PARENTAL AGE WITH CONGENITAL DEFECTS IN A CHILD
17.12.2021
Increased risks of having a child with chromosomal abnormalities such as Down syndrome exist in women after 35 years old, and men who conceive after 45 years old can induce dwarfism, although this does not mean that adults necessarily have children with disorders, Elena Baranova, PhD in medicine, associate professor of the Department of Medical Genetics of the Federal State Budgetary Educational Institution of Higher Medical Education of the Ministry of Healthcare of Russia, medical director of Evogen LLC, said to RIA Novosti.
The second scientific and educational student school-conference on genetics and biotechnology is taking place on December 13-19 at the educational center "Sirius". The conference program is prepared for undergraduate and graduate students specializing in genetics, molecular biology, biotechnology and neurobiology. According to the conference organizers, leading experts in genetics, biotechnology and neurobiology are involved in lectures, classes and master classes.
"Indeed, as females age, the risk of a fetus having chromosomal abnormalities increases. So, when we talk about a child having Down syndrome, it can mostly happen because of a woman's age risk, because after the age of 35 that risk increases, but to say that any increased woman age will necessarily have a child with a chromosomal abnormality, of course, that's not correct. Plus these women are always under specific control, they are at risk, which is the primary attention, and therefore such pregnancies are more carefully monitored. And in general, during pregnancy it is possible to suspect a chromosomal abnormality", - said Dr. Baranova.
However, the genetically determined disease risks also increase with the age of a man. According to Ph.D., among men this age goes over 45 years old and then one runs the risk of " point changes" in DNA sequence that may provoke dwarfism. And it's believed that as a man ages, the odds of these exact point changes in the DNA increase. Generally, we're talking about this risk for men over the age of 45. For example, it's achondroplasia - dwarfism. For this disease, the risk of de novo mutation (when parents do not have the mutation, but it occurs in the fetus - ed.) correlates with the age of the father", - explained the expert.
This is why no one can fully identify all the diseases in a genetic study and guarantee the birth of a healthy child even from healthy parents, explained Baranova. The earliest stage to detect any abnormalities would be testing a couple for being "carrier" of a disease, the associate professor of medical genetics department added.
In addition, if a man and a woman are carriers of a variant in the very same gene, for example, associated with diseases, such as cystic fibrosis and spinal muscular atrophy, there is a 25 percent chance that a disordered child may be born.
"Although we have a well known sequence of the genome, we don't have a thorough understanding of the whole sequence. Of course, we cannot guarantee, even if the man and woman are healthy and are not carriers, that a healthy child will be born. When we take a look at a couple's pattern of carriage, there are quite a number of diseases that the couple may not have, but specific mutations will occur in germ cells. For example, in a germ cell of the dad or a germ cell of the mom. These are so-called de novo diseases, i.e. parents have no such mutation, but their child will have one. Therefore, we definitely cannot detect such cases by determining the carriage," emphasized Baranova.
The expert added, that when a woman is currently pregnant, the disease can still be detected. Thus, today the technology is used to detect whether the fetus has a high risk of chromosomal abnormalities, such as Down syndrome, Patau syndrome and others, concluded Ph.D. in medical sciences.
The second scientific and educational student school-conference on genetics and biotechnology is taking place on December 13-19 at the educational center "Sirius". The conference program is prepared for undergraduate and graduate students specializing in genetics, molecular biology, biotechnology and neurobiology. According to the conference organizers, leading experts in genetics, biotechnology and neurobiology are involved in lectures, classes and master classes.
"Indeed, as females age, the risk of a fetus having chromosomal abnormalities increases. So, when we talk about a child having Down syndrome, it can mostly happen because of a woman's age risk, because after the age of 35 that risk increases, but to say that any increased woman age will necessarily have a child with a chromosomal abnormality, of course, that's not correct. Plus these women are always under specific control, they are at risk, which is the primary attention, and therefore such pregnancies are more carefully monitored. And in general, during pregnancy it is possible to suspect a chromosomal abnormality", - said Dr. Baranova.
However, the genetically determined disease risks also increase with the age of a man. According to Ph.D., among men this age goes over 45 years old and then one runs the risk of " point changes" in DNA sequence that may provoke dwarfism. And it's believed that as a man ages, the odds of these exact point changes in the DNA increase. Generally, we're talking about this risk for men over the age of 45. For example, it's achondroplasia - dwarfism. For this disease, the risk of de novo mutation (when parents do not have the mutation, but it occurs in the fetus - ed.) correlates with the age of the father", - explained the expert.
This is why no one can fully identify all the diseases in a genetic study and guarantee the birth of a healthy child even from healthy parents, explained Baranova. The earliest stage to detect any abnormalities would be testing a couple for being "carrier" of a disease, the associate professor of medical genetics department added.
In addition, if a man and a woman are carriers of a variant in the very same gene, for example, associated with diseases, such as cystic fibrosis and spinal muscular atrophy, there is a 25 percent chance that a disordered child may be born.
"Although we have a well known sequence of the genome, we don't have a thorough understanding of the whole sequence. Of course, we cannot guarantee, even if the man and woman are healthy and are not carriers, that a healthy child will be born. When we take a look at a couple's pattern of carriage, there are quite a number of diseases that the couple may not have, but specific mutations will occur in germ cells. For example, in a germ cell of the dad or a germ cell of the mom. These are so-called de novo diseases, i.e. parents have no such mutation, but their child will have one. Therefore, we definitely cannot detect such cases by determining the carriage," emphasized Baranova.
The expert added, that when a woman is currently pregnant, the disease can still be detected. Thus, today the technology is used to detect whether the fetus has a high risk of chromosomal abnormalities, such as Down syndrome, Patau syndrome and others, concluded Ph.D. in medical sciences.
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