Caudal Regression Syndrome


Caudal regression syndrome which is also known as Sacral agenesis; is a rare type of disorder that occurs when all or a part of the sacrum, or other bones of the lower spine is missing or misshapen, and the sections that correspond the spinal cord are missing or irregular as well.

There is a possibility that two out of five sacral segments will be missing without causing any problems. If three to five sacral segments are missing, abnormality of the nerves will probably come out of the sacrum.

caudal regression syndrome

The disorder impairs the caudal or the lower half of the body. The areas that can be affected are the gastrointestinal tract, the lower back and limbs, and the genitourinary tract. Caudal regression syndrome might present in isolation, or be linked with some other abnormalities like certain problems with the development of the joints or bones of the lower rib region, rectum, or anus.

The condition can occur in approximately 1 to 2.5 in 100,000 newborns. This disorder commonly appears in infants who are born to mothers with diabetes, in which it affects approximately 1 in 350 newborns. Caudal regression syndrome sporadically occurs, which means that individuals with no background of the condition in their family can have it. There are several environmental and genetic factors that may contribute in the development of this condition.

Symptoms of Caudal Regression Syndrome

The specified severity and symptoms of caudal regression syndrome greatly depends from one individual to another. The condition most probably represents a spectrum of disease that ranges from cases with mild to severe symptoms, disabling or even life-threatening complications.

caudal regression syndrome image

It is essential to remember that not all affected individuals experience the symptoms.

Symptoms of this condition may include:

  • Narrowed hips
  • Underdeveloped muscles of the buttock
  • Sacral dimple of the lower back
  • Flattening of the buttocks
  • Faulty bowel or bladder control
  • Failure of the bladder to entirely empty
  • Increased frequency of urinating
  • Flexion contractures of the hip and knee
  • Decreased muscle mass in the legs
  • Clubfeet
  • Facial abnormalities like cleft palate or lip
  • Kidney damage
  • Heart defects
  • Respiratory complications


Majority of the cases of caudal regression syndrome have no known cause. However, researchers believe that there are genetic and environmental factors that could play a role in the occurrence of the condition. Most patients with this condition sporadically appear which indicates a new mutation or environmental factors.

There is also a clear interrelation with insulin-dependent diabetes in mothers. The condition might also be associated with an abnormal development in certain organs like the joints and bones of the leg, rectum/anus, and other bones of the spine.


Caudal regression syndrome is divided into four groups depending on the total sacrum amount that is affected, and the essential qualities involving the articulation in between the pelvis and spine. These are:

  • Type I is the partial or total unilateral sacral agenesis
  • Type II is the partial sacral agenesis containing a bilateral symmetric defect, a normal or below normal sacral vertebra, and a balanced articulation of the first sacral vertebra and ilia
  • Type III involves variable lumbar and total sacral agenesis is where the ilia articulate itself towards the lower sides of the lowest vertebra that is present
  • Type IV – variable lumbar and total sacral agenesis, this is where the caudal endplate of the lowest vertebra rests itself, just above either any fused ilia or an iliac amphiarthrosis on the site


Most cases of caudal regression syndrome are only detected after birth though in some other cases, the disorder may later be discovered when the child is much older and experiences certain symptoms.

The diagnostic procedures may consist of:

  • Fetal ultrasound – This can distinguish some of the associated defects of the condition
  • Echocardiography – May be done to assess the degree of the involvement of the heart
  • Magnetic Resonance Imaging (MRI) – This is an imaging test that can produce cross-sectional images of specific tissues and organs of the body and it can help in evaluating the degree of some anomalies like spinal defects


Treatment for caudal regression syndrome is directly aimed towards the symptoms that are present in each individual. Treatment options may include:

Orthopedic devices – These may be used in individuals with problems of the legs, hip, and back.

Surgery – Problems like cleft lip or palate, anal atresia, cardiac or spinal abnormalities, extra toes or fingers, and other certain limb deformities related with the condition could be refined or corrected with a surgical procedure.

Anticholinergic drugs – These can also be administered by the physician to treat urological abnormalities.

Genetic counseling – This can be beneficial for both the patients and their families.


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caudal regression syndrome


  1. Inheritance patterns and prenatal diagnosis at
  4. Jeelani Y, Mosich GM, McComb JG (2013 Sep). Closed neural tube defects in children with caudal regression. Childs Nerv Syst. 29(9):1451-7.
  5. Thottungal AD, Charles AK, Dickinson JE, Bower C (2010 Oct). Caudal dysgenesis and sirenomelia-single centre experience suggests common pathogenic basis. Am J Med Genet A. 152A(10):2578-87.
  6. Boulas MM (2009 Apr). Recognition of caudal regression syndrome. Adv Neonatal Care. 9(2):61-9; quiz 70-1

9 thoughts on “Caudal Regression Syndrome

  • 05/02/2017 at 10:24 AM

    I actually have Caudal Regression and this was very informative! Thanks for trying to spread awareness for this rare disease!

    • 03/06/2017 at 8:49 AM

      Hi I would like to get in contact with you, any way we can talk? My daughter has been diagnosed with caudal regression…. I would like to know the process you went through, we are having a hard time understanding it and would like to speak to someone who has it…

    • 30/03/2021 at 1:51 PM

      my 18 year old daughter has caudal regression she is having alot of problems with her left arm and knee i do not know if this is normal with this condition she is at the emergency room right now we are scared and as a parent i feel very alone

  • 25/02/2017 at 12:37 AM

    We just found out my daughter was diagnosed with caudal regression. Syndrome I’ for her my heart breaks I wish it was me instead of her I have another child and he’s healthy because I hate to see her like this but I wanna better understand her diagnosis but don’t know where to turn to have someone me and help me better understand n take care or this horrible disease please someone contact me

    • 02/06/2017 at 5:17 AM

      My grandchild was birn with CRS.
      My daughter found a group, ISACRA you can find them on facebook and connect with other parents and people who have had CRS inpact their lives.

    • 03/06/2017 at 9:02 AM

      Hi, my daughter has been diagnosed as well, can you please contact me????? please I need to speak to someone that is going through this!!

  • 28/02/2017 at 4:56 PM

    Has casually found today this forum and it was specially registered to participate in discussion.

  • 07/02/2018 at 8:59 PM

    I have a 30 year old son with CRS. We took it one day one surgery at a time. There was not much info on this when he was young, but he grew and became a nurse. He is married and does ok lots of infections and many surgeries. As more info comes out he finds more anomalies in his skeleton.He works, but I doubt forever, his stamina isn’t great but considering he is a miracle. We went on to have two other “normal” daughters.

  • 25/06/2019 at 10:44 AM

    I was born with CRS and have always wondered how rare it is and now I know. I’ve had over 20 surgerys the last one was in Kindergarten and now i’m a normal kid. The one thing I want to know is this curable, it probably isn’t but i’m happy the way I am. I have to do a MACE clean out every day and there is another surgery that I could consider, but I think i’ll stay the way I am. Don’t give up hope!


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