Caudal regression sequence and deletion of 7q34-q36.3 region

Caudal regression sequence is a rare congenital disorder that involves a spectrum of congenital anomalies ranging from agenesis of the lumbosacral spine to the most severe cases of sirenomelia with lower extremity fusion. This disorder is often accompanied by damage to the spinal cord and various malformations of musculoskeletal, gastrointestinal, genitourinary and nervous systems. Most cases are sporadic or associated with gestational diabetes. It is believed that caudal regression sequence occurs during embryogenesis as a result of disturbance in mesoderm development. To date, pathogenic variants of HLXB9 gene in the 7q36.3 region were associated exclusively with the autosomal dominant form of sacral agenesis or Currarino syndrome. We report the fi rst case of caudal regression sequence caused by deletion of 7q34-q36.3 region, inherited from mother with balanced reciprocal translocation: 46,XX,t(7;18)(q35;q23), and highlight the important role of HLXB9 gene in development of sacrum and associated structures.

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