Caudal Regression Syndrome

A baby boy born at 37 weeks’ gestation via cesarean delivery for breech presentation
was noted to have marked malformation of the bilateral lower extremities with absent
proximal and distal segments, and left hallux conjoined with the second toe. Radiographs showed absence of the acetabulum, femur, tibia, fibula, and tarsal bones bilaterally. These findings were consistent with caudal regression syndrome.

Prenatal ultrasonograms in the second trimester had shown no lower extremities bilaterally; however, the mother, a 19-year-old primigravida, decided to carry the baby to term. The mother had poorly controlled type 1 diabetes; her hemoglobin A1C level during pregnancy was 8.3% (normal, 4% to 6%).

Caudal regression syndrome (caudal dysplasia sequence) is characterized by complete or partial agenesis of the sacral and lumbar vertebrae, along with pelvic deformity. Multiple other anomalies-including femoral hypoplasia; clubbed feet; flexion contractures of the lower
extremities; GI, genitourinary, and heart abnormalities; and neural tube defects-may also be associated with the syndrome.¹ A short crown-rump length may be noted in the first trimester; however, diagnosis is usually not made until later in the second trimester. Although most cases are sporadic, genetic factors may play a role in the development of caudal regression syndrome. The syndrome is much more likely to occur in children of mothers with diabetes than in children
of mothers without diabetes; up to 22% of cases are associated with either type 1 or type 2 diabetes mellitus in the mother.¹ Hyperglycemia is thought to be a causative factor.²

When this anomaly is noted, in addition to appropriate prenatal counseling, the extent of the caudal dysgenesis needs to be determined so that associated conditions, such as anal atresia and incontinence, can be treated.¹

This infant was breathing well on room air, and urinary output and bowel movements were normal. A renal ultrasonogram was normal, and echocardiography showed a closing patent ductus arteriosus. No other abnormalities were noted. After 14 days of evaluation in the neonatal ICU, the baby was discharged home with his mother and orthopedic follow-up was arranged.

References:

REFERENCES:

1.

Stroustrup Smith A, Grable I, Levine D. Case 66: caudal regression syndrome in the fetus of a diabetic mother.

Radiology.

2004;230:229-233.

2.

Zaw W, Stone DG. Caudal regression syndrome in twin pregnancy with type II diabetes.

J Perinatol.

2002;22:171-174.