I am just curious. Why is metabolic syndrome called syndrome X. I always thought that down syndrome (genetic disorder) is referred to as X syndrome but was surprised to see syndrome X here and then found out that the two are totally different. Just wondering where the X came from

It comes just after the W and before the Y.

You're mixing up two completely different things.

In Syndrome X, the "X" just means unknown. For the longest time, the medical community understood there was a syndrome, but lacked the knowledge to understand why. That knowledge is slowly increasing and so that's why we have terms like PCOS and insulin resistance, and everything else that falls in line with it. It's like the X just represented this large unknown. Kind of like why Malcolm X has X in his name, or why Generation X was named X.

In genetic disorders such as Downs Syndrom, it's an "x" disorder because the anomoly occurs on the X chromosome. Other genetic disorders are "y" disorders because they occur on the Y chromosome and thus affect only men.