Answer : Caudal regression syndrome or sacral agenesis the X ray clearly shows sacral agenesis There is well known association with DM, but now there is increased recognition of it's ass. with folic acid def. and in our patient on antiepileptic...the folc acid def. could have ebeen the underlying mechanism. Excerpts from wiki Caudal regression syndrome or sacral agenesis (or hypoplasia of the sacrum) is a congenital disorder in which there is abnormal fetal development of the lower spine—the caudal partition of the spine. It can lead to a variety of medical problems ranging from partial absence of the tail bone regions of the spine to more severe cases involving major malformation of the lower vertebrae, pelvis and spine. Minor cases may be more or less without symptom, whereas severe cases may come with major birth defects, neurological impairment (i.e. Flaccid paralysis of lower extremities) and incontinence. Synonyms for CRS: Caudal dysplasia Caudal dysplasia sequence Congenital sacral agenesis Sacral regression Lumbo sacral agenesis (-: