Why does a child have their mother’s eyes or their father’s height? Why do certain conditions appear in several members of a family? And when there is a genetic disease in the family, does it necessarily mean the child will inherit it?<\/p>\n
Heredity<\/strong> describes the passing of genetic information from parents to their children. Genetic information influences many characteristics of the human body \u2014 from blood group and certain features of appearance to a predisposition to specific conditions.<\/p>\n Reality, however, is more complex than “she got it from mum” or “he inherited it from dad”.<\/p>\n A child’s development and health are the result of a continuous interaction between their genes and the environment in which they grow up<\/strong>.<\/p>\n Almost every cell in the human body contains our genetic material, DNA<\/strong>.<\/p>\n We can imagine DNA as a huge set of biological instructions. Sections of DNA make up the genes<\/strong>, which contain information involved in the functioning and development of the body.<\/p>\n DNA is organised into structures called Most human cells have 46 chromosomes, arranged in 23 pairs<\/strong>. In each pair, as a rule, one chromosome comes from the mother and the other from the father.<\/p>\n So from the moment of fertilisation, the child acquires a unique combination of genetic material.<\/p>\n There is no simple answer.<\/p>\n For some characteristics the genetic influence is very strong. Others are significantly affected by the environment, while most complex human traits result from the Nutrition, physical activity, sleep, infections, exposure to substances, social circumstances and many other experiences can interact with a child’s biological predisposition.<\/p>\n This becomes especially important when we talk about development.<\/p>\n A child is not simply the “sum of their parents’ genes”. Their physical growth, learning, behaviour and health are shaped through a much more complex process.<\/p>\n The term genotype<\/strong> refers to a person’s genetic make-up.<\/p>\n The phenotype<\/strong> is their observable characteristics \u2014 not only outward appearance, but also many biological and functional traits.<\/p>\n The phenotype is not always a simple “copy” of the genotype. In many cases it is shaped by the interaction of genetic information with the environment.<\/p>\n No \u2014 and this is an important distinction.<\/p>\n A genetic disease<\/strong> is a disease associated with changes in the genetic material.<\/p>\n A hereditary disease<\/strong> is a genetic disease whose underlying genetic change can be passed from a parent to a child.<\/p>\n Therefore, all hereditary diseases are genetic, but not all genetic diseases are hereditary<\/strong>.<\/p>\n Some genetic changes may appear for the first time in the child, without having been inherited from either parent.<\/p>\n There is no single mode of inheritance.<\/p>\n Depending on the gene and the condition, there are different inheritance patterns.<\/p>\n In some diseases, a pathogenic variant in one of the two copies of a particular gene may be enough for the condition to appear.<\/p>\n When a parent carries such a variant, in a typical autosomal dominant pattern each of their children has a 50% chance of inheriting it<\/strong>.<\/p>\n The probability applies to each pregnancy separately<\/strong>. The outcome of a previous pregnancy does not change the probability for the next one.<\/p>\n A well-known example is familial hypercholesterolaemia<\/strong>, which can cause very high LDL cholesterol levels from childhood.<\/p>\n In other diseases, for the condition to appear the child needs to inherit a pathogenic variant in both copies of a particular gene.<\/p>\n The parents may be completely healthy When both parents carry pathogenic variants of the same gene, in a typical autosomal recessive pattern each pregnancy has:<\/p>\n a 25% chance<\/strong> that the child will have the condition, Here too, the probabilities repeat with every new pregnancy<\/strong>.<\/p>\n A classic example is beta-thalassaemia (Mediterranean anaemia)<\/strong>.<\/p>\n Some conditions are associated with genes located on the X chromosome.<\/p>\n In the more common X-linked recessive diseases, boys are usually more likely to develop the condition when they carry the relevant pathogenic variant, because they have only one X chromosome.<\/p>\n A typical example is haemophilia A<\/strong>.<\/p>\n However, X-linked inheritance is more complex than the old rule “the mother is a carrier and the boys are affected”. Girls or women who carry a pathogenic variant may, depending on the disease and the biological mechanisms, also have symptoms.<\/p>\n Not all genetic diseases are caused by a change in a single specific gene.<\/p>\n Sometimes there is a different number or structure of chromosomes. A well-known example is Down syndrome (trisomy 21)<\/strong>, in which there is an extra copy of the genetic material of chromosome 21.<\/p>\n Most cases of Down syndrome are not caused by inheriting an “abnormal gene” from a parent<\/strong>, but result from a chromosomal event during the formation of reproductive cells. There are, however, rarer forms in which the mechanism and the risk of recurrence are different.<\/p>\n This shows why genetic counselling must be based on the A genetic predisposition does not always mean certainty that someone will develop a condition.<\/p>\n For many common health problems \u2014 such as obesity, diabetes, high blood pressure and several other conditions \u2014 there is usually no single “disease gene”.<\/p>\n Many genetic variants, combined with environmental factors and lifestyle, may influence the overall risk.<\/p>\n That is why saying “there is an increased predisposition”<\/strong> is different from saying “the child will develop the disease”<\/strong>.<\/p>\n Family history remains one of the most useful tools in medicine.<\/p>\n The presence of specific diseases in parents, siblings or other close relatives can help the pediatrician decide whether a child needs earlier or different preventive screening<\/strong>.<\/p>\n For example, very high cholesterol or early cardiovascular disease in the family, certain blood disorders, unexplained pregnancy losses, congenital anomalies or a known genetic diagnosis may be important information.<\/p>\n That is why parents should inform the pediatrician about significant changes or new diagnoses in the family history.<\/p>\n Not every child needs genetic tests.<\/p>\n Genetic testing may be considered when there are, among other things, specific clinical findings, congenital anomalies, developmental difficulties with features that need investigation, a strong family history or a known genetic disease in the family.<\/p>\n The decision to carry out a genetic test is best made with a specific clinical question in mind.<\/p>\n A genetic test can provide valuable information, but it may also reveal findings of uncertain significance or information that concerns other family members. That is why interpreting the result is as important as the test itself.<\/p>\n Genetic counselling<\/strong> helps an individual or family understand a genetic diagnosis, how it may be inherited, the chances of it occurring or recurring and the testing options available.<\/p>\n Its purpose is not to decide on the family’s behalf.<\/p>\n The aim is to provide clear, evidence-based information<\/strong>, so that those involved can make their own decisions according to their needs and values.<\/p>\n When there is an increased likelihood of a specific genetic or chromosomal condition, testing options before or during pregnancy may be discussed.<\/p>\n An important distinction is needed here:<\/p>\n Prenatal screening<\/strong> estimates the probability that a specific condition is present, but usually does not by itself give a definitive diagnosis.<\/p>\n Diagnostic tests<\/strong>, such as chorionic villus sampling or amniocentesis in appropriately selected cases, can be used for a more definitive genetic or chromosomal investigation.<\/p>\n The available methods have advanced considerably, and the choice depends on the history, the stage of pregnancy and the specific question. The decision is made together with the obstetrician and, where appropriate, a clinical geneticist or genetic counsellor.<\/p>\n Modern genetics has helped us understand how important the genetic material we inherit is. At the same time, it has shown us that biology is far more complex than the idea that “one gene determines our life”.<\/p>\n For some genetic diseases the link between a genetic change and the disease is very strong. For many other traits and conditions, however, the outcome depends on many genes, the environment and their interaction throughout life<\/strong>.<\/p>\n For parents, the most important thing is to know their family history and discuss it with the pediatrician.<\/p>\n When there is a real indication, appropriate genetic investigation and counselling can provide answers, guide follow-up and help the family make informed decisions.<\/p>\n Our genes are an important part of our biological story \u2014 but in most cases, they are not the whole story.<\/strong><\/p>\n For appointments and information, contact Dr. Giannis Ritsas, pediatrician Thessaloniki<\/a> and pediatrician Evosmos<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" Why does a child have their mother’s eyes or their father’s height? Why do certain conditions appear in several members of a family? And when there is a genetic disease in the family, does it necessarily mean the child will inherit it? Heredity describes the passing of genetic information from parents to their children. Genetic […]<\/p>\n","protected":false},"author":5,"featured_media":2857,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[37],"tags":[],"class_list":["post-3008","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-nea-en"],"_links":{"self":[{"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/posts\/3008","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/comments?post=3008"}],"version-history":[{"count":1,"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/posts\/3008\/revisions"}],"predecessor-version":[{"id":3011,"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/posts\/3008\/revisions\/3011"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/media\/2857"}],"wp:attachment":[{"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/media?parent=3008"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/categories?post=3008"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.ritsas-paidiatros.gr\/en\/wp-json\/wp\/v2\/tags?post=3008"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}DNA, genes and chromosomes: in simple terms<\/h2>\n
\nchromosomes<\/strong>.<\/p>\nGenes and environment: which matters more?<\/h2>\n
\ninteraction of many genes with each other and with many environmental factors<\/strong>.<\/p>\nWhat are genotype and phenotype?<\/h2>\n
Is “genetic” the same as “hereditary”?<\/h2>\n
How are genetic diseases inherited?<\/h2>\n
Autosomal dominant inheritance<\/h2>\n
Autosomal recessive inheritance<\/h2>\n
\ncarriers<\/strong>.<\/p>\n
\na 50% chance<\/strong> that the child will be a carrier like the parents, and
\na 25% chance<\/strong> that the child will not inherit either of the two variants.<\/p>\nX-linked inheritance<\/h2>\n
What are chromosomal disorders?<\/h2>\n
\nspecific diagnosis<\/strong> and not on general rules.<\/p>\nWhat does “I have a hereditary predisposition” mean?<\/h2>\n
Why does the pediatrician care about family history?<\/h2>\n
When might genetic testing be needed?<\/h2>\n
What is genetic counselling?<\/h2>\n
Prenatal screening and prenatal diagnosis<\/h2>\n
Heredity is not destiny<\/h2>\n