X-Linked Dominant Inheritance
X-linked means the gene is located on the X chromosome, one of two sex chromosomes. Genes, like chromosomes, usually come in pairs. Dominant means that when there are two copies of the responsible gene, only one copy must have a disease-causing change (pathogenic variant) in order for a person to have the disease. Mutation is an older term that is still sometimes used to mean pathogenic variant.
Because women have two X chromosomes, a pathogenic variant for an X-lined dominant disease needs to occur in only one copy of the gene to cause the disease. Because men have one X chromosome and thus only one copy of the gene, a pathogenic variant in their one copy is enough to cause the disease. Women may experience less severe symptoms than men.
A woman who carries one X-linked gene variant has a 50% (1 in 2) chance of having a son or daughter with the disease. A man with an X-linked dominant disease cannot pass on the disease to his sons, but all of his daughters will have the disease. If a child is the first person in a family with the disease, the pathogenic variant may have occurred by chance for the first time in the child (de novo).X-linked means the gene is located on the X chromosome, one of two sex chromosomes. Genes, like chromosomes, usually come in pairs. Dominant means that when there are two copies of the responsible gene, only one copy must have a disease-causing change (pathogenic variant) in order for a person to have the disease. Mutation is an older term that is still sometimes used to mean pathogenic variant.
Because women have two X chromosomes, a pathogenic variant for an X-lined dominant disease needs to occur in only one copy of the gene to cause the disease. Because men have one X chromosome and thus only one copy of the gene, a pathogenic variant in their one copy is enough to cause the disease. Women may experience less severe symptoms than men.
A woman who carries one X-linked gene variant has a 50% (1 in 2) chance of having a son or daughter with the disease. A man with an X-linked dominant disease cannot pass on the disease to his sons, but all of his daughters will have the disease. If a child is the first person in a family with the disease, the pathogenic variant may have occurred by chance for the first time in the child (de novo).
Because women have two X chromosomes, a pathogenic variant for an X-lined dominant disease needs to occur in only one copy of the gene to cause the disease. Because men have one X chromosome and thus only one copy of the gene, a pathogenic variant in their one copy is enough to cause the disease. Women may experience less severe symptoms than men.
A woman who carries one X-linked gene variant has a 50% (1 in 2) chance of having a son or daughter with the disease. A man with an X-linked dominant disease cannot pass on the disease to his sons, but all of his daughters will have the disease. If a child is the first person in a family with the disease, the pathogenic variant may have occurred by chance for the first time in the child (de novo).X-linked means the gene is located on the X chromosome, one of two sex chromosomes. Genes, like chromosomes, usually come in pairs. Dominant means that when there are two copies of the responsible gene, only one copy must have a disease-causing change (pathogenic variant) in order for a person to have the disease. Mutation is an older term that is still sometimes used to mean pathogenic variant.
Because women have two X chromosomes, a pathogenic variant for an X-lined dominant disease needs to occur in only one copy of the gene to cause the disease. Because men have one X chromosome and thus only one copy of the gene, a pathogenic variant in their one copy is enough to cause the disease. Women may experience less severe symptoms than men.
A woman who carries one X-linked gene variant has a 50% (1 in 2) chance of having a son or daughter with the disease. A man with an X-linked dominant disease cannot pass on the disease to his sons, but all of his daughters will have the disease. If a child is the first person in a family with the disease, the pathogenic variant may have occurred by chance for the first time in the child (de novo).
