Simply: reverse of OTL situation happens-in 1503 Queen Anne gives birth to a healthly son, in 1506 she dies giving birth to a daughter, who due to difficutlies at birth (hypoxia) is retarded. What impact would that change have?
Vladislaus' firstborn is healthly son, so there are less concerns about succession, especially among anti-Habsburg national party, whose leaders were Zapolyas. IOTL birth of Anna caused conflict between Vladislaus and Zapolya, King promised to HRE Maximilian that Anna would marry his grandson, at the same time promising to Zapolya that she would not marry Habsburg prince (nothing unusual for rex bene).
With Jagiellon succession in Hungary being more secure following changes would happen:
-Janos Zapolya, instead of trying to get hand of Vladislaus' daughter, who was outside his reach, marries Vladislaus' Hohenzollern niece instead (Margaret of Ansbach) as was planned.
-Sigismund the Old would likely not marry Barbara Zapolya in such case. IOTL Sigismund, who had bad relations with Habsburga before First Congress of Vienna in 1515, due to their support for Teutonic Order, was concerned about possibility of Habsburg succession in Hungary, with only retarded Louis between Habsburgs and Hungarian throne, thus to strenghten position of Janos Zapolya-leader of anti-Habsburg party, he married his sister. ITTL that is not necessary, especially if Janos Zapolya is already married to half-Jagiellon girl. That means another wife for Sigismund, possibly Catherine of Mecklenburg, whom he planned to marry before Barbara. That would have interesting consequences, taking into account Catherine's Protestant leanings.
-For Habsburgs something like OTL deal made in Vienna in 1515 would be less favorable. Their succession in Bohemia and Hungary is less likely than IOTL, and if Anna of Bohemia and Hungary is female version of OTL Louis II perspective of marriage with her would not make Ferdinand happy...
-Louis II being 13 instead of 10 at the time of father's death means, that degenerate Georg Hohenzollern has less time to "raise" his Jagiellon cousin.
-Even under sane Louis II Kingdom of Hungary can't resist Ottomans. So either Louis would try diplomatic means to save Hungary or some crushing defeat would still happen.