Review Question - QID 106476

This child, presenting with urinary incontinence and small, paralyzed lower limbs in the setting of lower body bone abnormalities has caudal regression syndrome (CRS). CRS has been associated with uncontrolled maternal diabetes during pregnancy.

CRS, also called sacral agenesis syndrome, is the result of a neural tube defect resulting in hypoplasia/agenesis of the lumbar spine or sacrum. The exact etiology of CRS is unknown but there is an increased incidence of CRS in children born to women with diabetes. Clinical findings of CRS include bony abnormalities of the lower spine and pelvis on radiographic imaging, bowel or bladder incontinence, and limb deformities. CRS can present in the setting of syndromes such as VACTERL (Vertebral, Anorectal, Cardiac, Tracheoesophageal fistula, Renal and Limb anomalies).

Boulas reviews CRS. CRS is rare with an unknown pathogenesis. However, as many as 22% of newborns with CRS are born to mothers with type 1 or type 2 diabetes. CRS is therefore considered to be one of the most characteristic complications of maternal diabetes.

Singh et al. also review CRS including associated anomalies and prognosis. Non-musculoskeletal systems which may be affected in the setting of CRS include the gastrointestinal and genitourinary systems. While many patients are able to live otherwise normal lives despite their lower limb defects, urological function in patients with CRS should be monitored closely in order to prevent renal damage caused by a neurogenic bladder or other urogenital anomalies.

Illustration A shows a newborn with CRS presenting with significant lower limb abnormalities.

Incorrect Answers:
Answer 1: Maternal hyperthyroidism is not associated with caudal regression syndrome.
Answer 3: Maternal use of tetracyclines is associated with discolored teeth, not caudal regression syndrome.
Answer 4: Maternal use of lithium is associated with Ebstein's anomaly, not caudal regression syndrome.
Answer 5: Maternal use of nicotine is associated with premature delivery, low birth weight, intrauterine growth retardation and ADHD, not caudal regression syndrome.