SNP Shot: Genomic Insights

Caudal regression syndrome (CRS) is a rare condition present at birth that affects the lower (caudal) portion of the body's development. The lower back, legs, genitourinary system, and gastrointestinal system can all be impacted.

A common characteristic of CRS is malformation or absence of the vertebrae in the lower spine. The corresponding sections of the spinal cord may also be affected in the same way. Manifestations can include incomplete vertebral closure, a fluid-filled sac on the back (possibly containing spinal cord tissue), or a tuft of hair at the base of the spine. Scoliosis, an abnormal curvature of the spine, can also occur. These spinal issues can affect chest size and shape, sometimes resulting in breathing difficulties.

Individuals with CRS might have small hip bones and limited hip mobility. The buttocks often appear flat and dimpled. The leg bones, particularly the femurs, are frequently underdeveloped. Some individuals have legs that are bent outwards, with knees pointing sideways and feet tucked under the hips, resembling a "frog leg" position. Clubfeet (feet turning inwards and upwards) or calcaneovalgus (feet turning outwards and upwards) can also be present at birth. Decreased sensation in the lower limbs is another possible symptom.

Genitourinary abnormalities are highly variable in CRS. Kidney malformations are common, including unilateral renal agenesis (missing kidney), horseshoe kidney (fused kidneys), or ureteral duplication (duplicated tubes carrying urine from the kidneys to the bladder). These issues can lead to frequent urinary tract infections and progressive kidney failure. Bladder exstrophy, where the bladder protrudes through an abdominal wall opening, can also occur. Neurogenic bladder, caused by nerve damage affecting bladder control, can result in increasing difficulty controlling urine flow. Genital abnormalities in males can include hypospadias (urethra opening on the underside of the penis) or cryptorchidism (undescended testes). Females may have a rectovaginal fistula (abnormal connection between the rectum and vagina). In the most severe cases, both males and females may experience genital agenesis (lack of genital development).

Gastrointestinal problems in CRS can involve malrotation of the large intestine, imperforate anus (blocked anal opening), inguinal hernias (soft bulges in the lower abdomen), or other digestive tract malformations. Constipation is common, and affected individuals may experience bowel and bladder incontinence.

Inheritance:

CRS typically occurs sporadically, meaning it is not inherited. It appears in individuals with no family history of the condition. The risk of developing CRS is likely influenced by a combination of genetic and environmental factors.