Prader-Willi syndrome is caused by a missing gene on chromosome 15. Normally, parents each pass down a copy of this chromosome. The defect can occur in a couple of ways: The father's genes are missing on chromosome 15.
: easy for the mind to understand or recognize. 1  It was obvious that things weren't working out. 2  Her reasons for leaving were obvious. = It's obvious why she left. 3  The answer seems obvious enough to me.  The problem was immediately obvious to everyone in the 1  room. He was the obvious candidate/choice for president.
apparent (comparative more apparent, superlative most apparent) 1  Capable of being seen, or easily seen; open to view; visible to the eye, eyely; within sight or view. 1667, John Milton, Paradise Lost, Book IV, [â¦] Hesperus, that led / The starry host, rode brightest, till the moon, / Rising in clouded majesty, at length / Apparent queen unveiled her peerless light, / And oâer the dark her silver mantle threw.