Activins
Activins are gonadal polypeptide hormones that are potent stimulators of FSH secretion and release in vitro.
Activins are dimers of 2 beta subunits that share extensive sequence homology with transforming growth factor-beta (TGFB) (MIM.190180).
There are 2 classes of activin receptors, type I and type II.
Pathology
germline mutations in left-right axis malformations (situs ambiguus)
- ventricular inversion (dextrocardia), but intact ventricular septum and normally related great arteries with right aortic arch and a right-sided spleen, and anomalies of the inferior and the superior vena cava.
- complete atrial ventricular canal defect with dextro-transposed great arteries and obstruction to pulmonary outflow (normal pulmonary venous return) with interrupted inferior vena cava with azygous continuation, polysplenia and medial liver (midline liver)
References
Kosaki, R.; Gebbia, M.; Kosaki, K.; Lewin, M.; Bowers, P.; Towbin, J. A.; Casey, B. : Left-right axis malformations associated with mutations in ACVR2B, the gene for human activin receptor type IIB. Am. J. Med. Genet. 82: 70-76, 1999. PubMed ID : 9916847