Skip to content

    Health & Pregnancy

    Font Size
    A
    A
    A

    Carrier Test for Autosomal Recessive Diseases

    h9991037.gif

    © Healthwise, Incorporated

    Autosomal recessive diseases are genetic diseases that are passed to a child through both parents' chromosomes. Autosomal recessive diseases include Tay-Sachs disease, cystic fibrosis, sickle cell anemia, autosomal recessive polycystic kidney disease (ARPKD), and phenylketonuria (PKU).

    Each person inherits 23 chromosomes from each parent and so has 23 pairs of chromosomes. Each chromosome contains genes. One or both of the chromosomes in a pair can carry a mutation and be abnormal or defective in a way that causes a genetic disease. In an autosomal recessive disease, both chromosomes in a pair must have a defective gene for the person to have the disease. If only one gene is defective, the person is a carrier of the disease but does not have any symptoms.

    Carrier test information for autosomal recessive diseases
    One parent is a carrier Both parents are carriers

    If only one parent carries the abnormal gene, there is:

    • A 50% chance in each pregnancy that their child will receive the defective gene and be a carrier.
    • A 50% chance in each pregnancy that their child will not receive the defective gene and will not be a carrier or have the disease.
    • Almost no chance that their child will have the disease.

    If both parents carry the abnormal gene, there is:

    • A 25% chance in each pregnancy that their child will inherit the defective gene from each parent (two genes) and have the disease.
    • A 50% chance in each pregnancy that their child will receive one defective gene and be a carrier.
    • A 25% chance in each pregnancy that their child will not receive the defective gene and will not be a carrier or have the disease.

    ByHealthwise Staff
    Primary Medical ReviewerKathleen Romito, MD - Family Medicine
    Specialist Medical ReviewerSiobhan M. Dolan, MD, MPH - Reproductive Genetics

    Current as ofMarch 12, 2014

    WebMD Medical Reference from Healthwise

    Last Updated: March 12, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

    Pregnancy Week-By-Week Newsletter

    Delivered right to your inbox, get pictures and facts on
    what to expect each week of your pregnancy.

    Today on WebMD

    hand circling date on calendar
    Track your most fertile days.
    woman looking at ultrasound
    Week-by-week pregnancy guide.
     
    Pretty pregnant woman timing contaction pains
    The signs to watch out for.
    pregnant woman in hospital
    Are there ways to do it naturally?
     
    slideshow fetal development
    Slideshow
    pregnancy first trimester warning signs
    Article
     
    What Causes Bipolar
    Video
    Woman trying on dress in store
    Slideshow
     
    pregnant woman
    Article
    Woman looking at pregnancy test
    Quiz
     
    calendar and baby buggy
    Tool
    dark chocolate squares
    Slideshow