Patty is the English diminutive of Patricia — from the Latin patricius ("noble, of the patrician class"). Patty Duke (1946-2016) — American actress; Academy Award for Best Supporting Actress for The Miracle Worker (1962) at age 16 — at the time the youngest competitive Oscar winner ever (a record she held for 24 years until Tatum O'Neal in 1973); reprised the Helen Keller story for which she had won the Tony at age 13. Open about her bipolar I disorder diagnosis — co-authored Brilliant Madness (1992) which is credited with reducing stigma.
Patty does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Patty reduce to 1, The Leader. This is a traditional interpretive system, not a factual claim about the name.