abnormal allele造句

• Persons affected by any forms of the disease have two abnormal alleles, and both parents are usually heterozygotes ( or carriers ).
• The most common abnormal alleles of this condition impair both the 17?-hydroxylase activity and the 17, 20-lyase activity of CYP17A1.
• If female, fetal DNA is analyzed to see if she carries one of the known abnormal alleles of the " CYP21 " gene.
• A very small number of people have reportedly had an abnormal allele that resulted primarily in a reduction of 17, 20-lyase activity, rather than both the hydroxylase and lyase activities as described above.
• When both parents carry an abnormal allele, each child has a 25 % chance of having the disease, a 50 % chance of being a carrier like the parents, and a 25 % chance of having two normal genes.
• "' Sickle cell trait "'( or "'sicklemia "') describes a condition in which a person has one abnormal allele of the hemoglobin beta gene ( is heterozygous ), but does not display the severe symptoms of sickle cell disease that occur in a person who has two copies of that allele ( is homozygous ).