Genetics of neurofibromatosis type 1 (NF1)GGenetics of neurofibromatosis type 1 (NF1)Genetics of neurofibromatosis type 1 (NF1)EnglishGeneticsChild (0-12 years);Teen (13-18 years)Eyes;SkinSkin;NervesConditions and diseasesCaregivers Adult (19+)NA2010-03-05T05:00:00ZElena Pope, MD, MSc, FRCPC;Patricia Parkin, MD, FRCPC;Stephen Meyn, MD, PhD, FRCPC, FACMG;Andrea Shugar, MS, CGC, CCGC6.3000000000000073.8000000000000768.000000000000Health (A-Z) - ConditionsHealth A-Z<p>Neurofibromatosis Type 1 (NF1) occurs because of a mutation to the NF1 gene. About half of cases are spontaneous mutations, while the other half are inherited from a parent to a child.</p><h2>What is a gene?</h2> <figure> <span class="asset-image-title">What are genes?</span> <img src="https://assets.aboutkidshealth.ca/akhassets/What_is_a_gene_MED_ILL_EN.jpg" alt="Cell, chromosome, DNA strand, gene and DNA building blocks or nucleotides" /> <figcaption class="asset-image-caption">Genes are made of long strings of nucleotides on a section of DNA. Groups of genes are packed tightly in a chromosome.</figcaption></figure> <p>Our bodies are made up of billions of cells. The cells work together to make our bodies work. Different cells have different jobs, but they all have one thing in common: each contains genes. </p><p>Genes are the instructions that our cells use to make proteins. Genes tell our cells how to work and what to do. For example, one gene may determine the colour of your hair or your blood type. </p><p>Genes are packaged in the form of chromosomes. The information in a gene is coded in a chemical called DNA.</p><p>There are about 30,000 genes inside every cell. Each person carries two copies of each gene. A child gets (inherits) one copy from their mother and the other from their father.</p><p>For more information about genes, please see the AboutKidsHealth section on <a href="/En/HowTheBodyWorks/GeneticsIntroduction" target="_blank">How the Body Works: Genetics.</a></p><h2>What causes NF1?</h2><p>Every person has two copies of the NF1 gene. This gene codes for a protein called neurofibromin (say: noor-oh-fie-BROH-min).</p><p>Neurofibromin's job in the body is to make sure that certain cells divide and grow in a controlled way. In particular, it stops certain cells that support the nerves from growing too much. These cells are called nerve sheath cells. </p><p>A mutation (a change in the genetic code) in the NF1 gene leads to a neurofibromin protein that does not work properly. This leads to symptoms of NF1. </p><h2>Key points</h2> <ul> <li>A person can get NF1 in one of two ways. Half of cases happen completely by chance. The rest of the time, NF1 is inherited or passed down from parent to child.</li> <li>In some cases, the signs or symptoms of NF1 are so mild that a parent may not find out they have NF1 until a child is diagnosed. </li> <li>A person with NF1 has a 50% (one in two) chance to have an affected child with each pregnancy. </li> <li>Adults may benefit from genetic counselling to understand their risks and choices regarding planning and family. </li> </ul><h2>There are two ways to get NF1<br></h2><p>There are two ways a person can get NF1: as a new mutation, or by inheriting it from a parent.</p><h3>A new (spontaneous) mutation</h3><p>Half of all cases of NF1 occur by chance. This is called a new or spontaneous mutation. A change occurs in the NF1 gene at the time of, or shortly after, conception. Conception is the time when the father's sperm and the mother's egg join and the egg is fertilized. </p><p>In this case, neither parent of the affected child will have NF1. Spontaneous gene mutations are not inherited from either parent. </p><h3>Inherited from a parent with NF1</h3><p>The other half of people with NF1 inherited it from one of their parents. This means that a parent with a mutation in the NF1 gene passed the mutated gene to the child. </p><p>In some cases, the signs or symptoms of NF1 are so mild that a parent may not find out they have NF1 until their child is diagnosed. </p><h2>How NF1 is inherited</h2><p>Genes come in pairs, as do the chromosomes that carry them. When we have children, each parent passes half of their genetic material to their children, meaning one gene from each pair of genes. </p> <figure class="asset-c-80"> <span class="asset-image-title">Heredity of neurofibromatosis (NF1)</span> <img src="https://assets.aboutkidshealth.ca/akhassets/Neurofibromatosis_genetics_MED_ILL_EN.jpg" alt="Chromosome distribution from an affected parent with one chromosome with NF1 gene mutation an unaffected parent" /> <figcaption class="asset-image-caption">Every person has 2 copies of the NF1 gene, one on each chromosome. If a person has one mutated NF1 gene, he or she may develop the conditions of neurofibromatosis. An affected parent has a 50% chance of passing the mutated gene on to his or her child.</figcaption> </figure> <p>NF1 is inherited as a dominant condition. Dominant means the mutated gene is stronger than the normal gene. This means that only one NF1 gene needs to be mutated for the person to develop NF1. </p><p>If a person has NF1, they have one normal NF1 gene and one NF1 gene with a mutation. When this person has a child, they can pass on either the normal NF1 gene or the NF1 gene with the mutation. In other words, a person with NF1 has a 50% (one in two) chance of passing on NF1 to their children. </p><p>Adults with NF1 who are planning a family may wish to seek genetic counselling so that they can understand their risks and choices. </p>
Neurofibromatose de type 1 (NF1): les causes génétiquesNNeurofibromatose de type 1 (NF1): les causes génétiquesGenetics of neurofibromatosis type 1 (NF1)FrenchGeneticsChild (0-12 years);Teen (13-18 years)Eyes;SkinSkin;NervesConditions and diseasesCaregivers Adult (19+)NA2010-03-05T05:00:00ZElena Pope, MD, MSc, FRCPC;Patricia Parkin, MD, FRCPC;Stephen Meyn, MD, PhD, FRCPC, FACMG;Andrea Shugar, MS, CGC, CCGC6.0000000000000071.0000000000000555.000000000000Health (A-Z) - ConditionsHealth A-Z<p>La neurofibromatose de type 1 (NF1) se produit en raison d'une mutation du gène NF1.</p><h2>Qu'est-ce qu'un gène?</h2> <figure> <span class="asset-image-title">Que sont les gènes?</span><img src="https://assets.aboutkidshealth.ca/akhassets/What_is_a_gene_MED_ILL_FR.jpg" alt="Une cellule, un chromosome, un brin d’ADN, un gène et des éléments constitutifs de l’ADN ou nucléotides" /><figcaption class="asset-image-caption"> Les gènes se composent de longs brins de nucléotides qui composent des sections d'ADN. Des groupes de gènes sont étroitement entassés pour former un chromosome. </figcaption> </figure> <p>Nos corps se composent de milliards de cellules. Elles travaillent de concert pour faire fonctionner nos corps. Les cellules n'ont pas toutes les mêmes fonctions mais elles ont toutes une chose en commun : elles contiennent des gènes.</p><p>Les gènes sont les instructions que nos cellules utilisent pour fabriquer des protéines. Les gènes disent à nos cellules comment travailler et quoi faire. Par exemple, un gène peut déterminer la couleur de nos cheveux ou notre groupe sanguin.</p><p>Les gènes sont regroupés en chromosomes. Les renseignements que contient un gène sont encodés dans une substance chimique nommée ADN.</p><p>Il y a environ 30 000 gènes dans chaque cellule. Chaque personne a deux copies de chaque gène. L'enfant en hérite une copie de sa mère et une autre de son père.</p><p>Pour plus de renseignements sur les gènes, consultez notre section <a href="https://pie.med.utoronto.ca/htbw/module.html?module=genetics" target="_blank">Le fonctionnement du corps humain: la génétique​</a>.</p><h2>Qu'est-ce qui provoque la NF1</h2><p>Chaque personne a deux copies du gène NF1. Ce gène code une protéine nommée neurofibromine. </p><p>Le rôle de la neurofibromine consiste à s'assurer que certaines cellules se divisent et prolifèrent de façon contrôlée. En particulier, elle empêche certaines cellules de la gaine nerveuse de trop se multiplier.</p><p>Une mutation (un changement dans le code génétique) du gène NF1 crée une protéine neurofibromine qui ne fonctionne pas correctement. Cela provoque les symptômes associés à la NF1.</p><h2>À retenir</h2> <ul> <li>Il y a deux façons de contracter la NF1. La moitié des cas se produit complètement par hasard. Le reste du temps, la NF1 est héritée ou transmise par l'un des parents à l'enfant.</li> <li>Dans certains cas, les signes ou les symptômes de NF1 sont tellement bénins que le parent ne réalise pas qu'il souffre de NF1 jusqu'à ce qu'on la détecte chez son enfant.</li> <li>Une personne qui souffre de NF1 a 50 % de chances (une chance sur deux) de transmettre ce gène à son enfant à chaque grossesse.</li> <li>Il pourrait être avantageux pour les adultes d'obtenir des conseils génétiques afin de comprendre les risques et les choix qui s'offrent à eux s'ils prévoient d'avoir des enfants.​</li> </ul><h2>Il y a deux façons de contracter la NF1</h2><p>Il y a deux façons de contracter la NF1: une nouvelle mutation se produit ou on l'hérite de l'un des deux parents.</p><h3>Une n​ouvelle mutation (spontanée)</h3><p>La moitié de tous les cas de NF1 se produit par hasard. C'est ce que l'on nomme une nouvelle mutation ou une mutation spontanée. Un changement se produit dans le gène NF1 au moment de la conception, ou peu après. La conception est le moment où le sperme du père et l'œuf de la mère s'unissent, et l'œuf s'en trouve donc fécondé. </p><p>Dans un tel cas, ni l'un ni l'autre des parents de l'enfant atteint ne souffre de NF1. Les mutations génétiques spontanées ne sont pas héritées de l'un des parents.</p><h3>Héritée d'un parent ​atteint de NF1</h3><p>Dans l'autre moitié des cas, les personnes atteintes de NF1 l'ont héritée de l'un des parents. Cela signifie que le gène NF1 avait subi une mutation chez le père ou la mère et a été transmis à l'enfant.</p><p>Dans certains cas, les signes ou les symptômes de NF1 sont tellement bénins que le parent pourrait ne pas savoir qu'il souffre de NF1 jusqu'à ce qu'on détecte cette maladie chez son enfant.<br></p><h2>Comment hérite-t-on de la NF1?</h2><p>Les gènes se présentent en paires, tout comme les chromosomes qui les transportent. Lorsqu'un enfant est conçu, chaque parent transmet la moitié de ses gènes à l'enfant, soit un gène pour chaque paire de gène. </p> <figure class="asset-c-80"> <span class="asset-image-title">Caractère héréditaire de la neurofibromatose (NF1)</span><img src="https://assets.aboutkidshealth.ca/akhassets/Neurofibromatosis_genetics_MED_ILL_FR.jpg" alt="Distribution des chromosomes d’un parent portant un chromosome avec mutation génétique du NF1 et d'un parent non atteint" /><figcaption class="asset-image-caption">Chaque être humain a 2 copies du gène NF1, un sur chaque chromosome. Pour les personnes chez qui l'un des gènes NF1 a subi une mutation, il est possible qu'elles développent la neurofibromatose. Les parents qui en sont atteints ont une chance sur deux de transmettre le gène muté à leur enfant.</figcaption></figure> <p>La NF1 est une maladie héréditaire dominante. Cela signifie que le gène muté est plus fort que le gène normal. Donc, il suffit que l'un des gènes NF1 soit muté pour que la personne développe la NF1.</p><p>Les personnes atteintes de NF1 ont un gène NF1 normal et un gène NF1 muté. Lorsque cette personne a des enfants, elle pourrait transmettre soit le gène NF1 normal ou le gène NF1 muté. En d'autres termes, une personne atteinte de NF1 a 50 % de chances (une chance sur deux) de transmettre la NF1 à ses enfants. </p><p>On recommande que les adultes atteints de NF1 qui prévoient d'avoir des enfants obtiennent une consultation génétique afin de comprendre les risques et les choix qui s'offrent à eux.</p>

 

 

 

 

Genetics of neurofibromatosis type 1 (NF1)866.000000000000Genetics of neurofibromatosis type 1 (NF1)Genetics of neurofibromatosis type 1 (NF1)GEnglishGeneticsChild (0-12 years);Teen (13-18 years)Eyes;SkinSkin;NervesConditions and diseasesCaregivers Adult (19+)NA2010-03-05T05:00:00ZElena Pope, MD, MSc, FRCPC;Patricia Parkin, MD, FRCPC;Stephen Meyn, MD, PhD, FRCPC, FACMG;Andrea Shugar, MS, CGC, CCGC6.3000000000000073.8000000000000768.000000000000Health (A-Z) - ConditionsHealth A-Z<p>Neurofibromatosis Type 1 (NF1) occurs because of a mutation to the NF1 gene. About half of cases are spontaneous mutations, while the other half are inherited from a parent to a child.</p><h2>What is a gene?</h2> <figure> <span class="asset-image-title">What are genes?</span> <img src="https://assets.aboutkidshealth.ca/akhassets/What_is_a_gene_MED_ILL_EN.jpg" alt="Cell, chromosome, DNA strand, gene and DNA building blocks or nucleotides" /> <figcaption class="asset-image-caption">Genes are made of long strings of nucleotides on a section of DNA. Groups of genes are packed tightly in a chromosome.</figcaption></figure> <p>Our bodies are made up of billions of cells. The cells work together to make our bodies work. Different cells have different jobs, but they all have one thing in common: each contains genes. </p><p>Genes are the instructions that our cells use to make proteins. Genes tell our cells how to work and what to do. For example, one gene may determine the colour of your hair or your blood type. </p><p>Genes are packaged in the form of chromosomes. The information in a gene is coded in a chemical called DNA.</p><p>There are about 30,000 genes inside every cell. Each person carries two copies of each gene. A child gets (inherits) one copy from their mother and the other from their father.</p><p>For more information about genes, please see the AboutKidsHealth section on <a href="/En/HowTheBodyWorks/GeneticsIntroduction" target="_blank">How the Body Works: Genetics.</a></p><h2>What causes NF1?</h2><p>Every person has two copies of the NF1 gene. This gene codes for a protein called neurofibromin (say: noor-oh-fie-BROH-min).</p><p>Neurofibromin's job in the body is to make sure that certain cells divide and grow in a controlled way. In particular, it stops certain cells that support the nerves from growing too much. These cells are called nerve sheath cells. </p><p>A mutation (a change in the genetic code) in the NF1 gene leads to a neurofibromin protein that does not work properly. This leads to symptoms of NF1. </p><h2>Key points</h2> <ul> <li>A person can get NF1 in one of two ways. Half of cases happen completely by chance. The rest of the time, NF1 is inherited or passed down from parent to child.</li> <li>In some cases, the signs or symptoms of NF1 are so mild that a parent may not find out they have NF1 until a child is diagnosed. </li> <li>A person with NF1 has a 50% (one in two) chance to have an affected child with each pregnancy. </li> <li>Adults may benefit from genetic counselling to understand their risks and choices regarding planning and family. </li> </ul><h2>There are two ways to get NF1<br></h2><p>There are two ways a person can get NF1: as a new mutation, or by inheriting it from a parent.</p><h3>A new (spontaneous) mutation</h3><p>Half of all cases of NF1 occur by chance. This is called a new or spontaneous mutation. A change occurs in the NF1 gene at the time of, or shortly after, conception. Conception is the time when the father's sperm and the mother's egg join and the egg is fertilized. </p><p>In this case, neither parent of the affected child will have NF1. Spontaneous gene mutations are not inherited from either parent. </p><h3>Inherited from a parent with NF1</h3><p>The other half of people with NF1 inherited it from one of their parents. This means that a parent with a mutation in the NF1 gene passed the mutated gene to the child. </p><p>In some cases, the signs or symptoms of NF1 are so mild that a parent may not find out they have NF1 until their child is diagnosed. </p><h2>How NF1 is inherited</h2><p>Genes come in pairs, as do the chromosomes that carry them. When we have children, each parent passes half of their genetic material to their children, meaning one gene from each pair of genes. </p> <figure class="asset-c-80"> <span class="asset-image-title">Heredity of neurofibromatosis (NF1)</span> <img src="https://assets.aboutkidshealth.ca/akhassets/Neurofibromatosis_genetics_MED_ILL_EN.jpg" alt="Chromosome distribution from an affected parent with one chromosome with NF1 gene mutation an unaffected parent" /> <figcaption class="asset-image-caption">Every person has 2 copies of the NF1 gene, one on each chromosome. If a person has one mutated NF1 gene, he or she may develop the conditions of neurofibromatosis. An affected parent has a 50% chance of passing the mutated gene on to his or her child.</figcaption> </figure> <p>NF1 is inherited as a dominant condition. Dominant means the mutated gene is stronger than the normal gene. This means that only one NF1 gene needs to be mutated for the person to develop NF1. </p><p>If a person has NF1, they have one normal NF1 gene and one NF1 gene with a mutation. When this person has a child, they can pass on either the normal NF1 gene or the NF1 gene with the mutation. In other words, a person with NF1 has a 50% (one in two) chance of passing on NF1 to their children. </p><p>Adults with NF1 who are planning a family may wish to seek genetic counselling so that they can understand their risks and choices. </p>https://assets.aboutkidshealth.ca/akhassets/What_is_a_gene_MED_ILL_EN.jpgGenetics of neurofibromatosis type 1 (NF1)False