Nephrotic syndrome and situs inversus viscerum: correlation or coincidence.

Asymmetric human internal organ organization has been a research topic for many years. Currently, although we know many mechanisms leading to the creation of specific internal organ organization, the problem requires further investigation. Transforming Growth Factor-beta superfamily (TGF-beta SF) molecules seem to play a major role in the process. They affect the cell by signaling through type I and II serine/threonine kinase receptors. Smad proteins seem vital in transmitting the signal between the receptor and the nucleus. We present the case of an 18-year-old female patient, who was admitted to the hospital because of steroid-sensitive nephrotic syndrome. Physical examination revealed that the patient also had a complete reversal of the intra-abdominal anatomy - situs inversus totalis. We suggest that disturbed TGF-beta and Smad signaling could be responsible for both nephrotic syndrome and situs inversus totalis.