Hypoplastic Left Heart Syndrome (HLHS) is a congenital heart defect that occurs randomly in about 1 out of 6,000 births and essentially means that the left side of Max's heart was underdeveloped and was not functioning properly.
In order to correct this, HLHS babies generally need to undergo a series of three surgeries to reroute the blood flow to allow it to circulate properly through his body. However, in Max's case, the right side of his heart had some pretty severe valve regurgitation and his best chances for survival were to go directly for a heart transplant instead of the three surgeries (which might have led to an eventual transplant anyway). We're working with an excellent cardiology team at Phoenix Children's Hospital and are feeling optimistic about Max's chances.
Without medical intervention, Max's heart would not have be able to function and he wouldn't have made it. We are very fortunate that the doctors were able to detect his HLHS when they did because otherwise, he would have died within the first couple weeks of his life and it most likely would have been attributed to Sudden Infant Death Syndrome (SIDS).
Thus far, doctors and researchers do not know what causes HLHS. The oldest person with this diagnosis is only 32 at the time of this writing so it is still a relatively "new" congenital heart defect. However, considering how many advances have already been made in working to alleviate the complications with this defect, medicine will be hopefully be able to continue to improve the diagnosis and treatment of HLHS.