Q99.2

Fragile X chromosome

Risk-adjusting (HCC)Billable code

HCC risk adjustment mapping

RxHCC V08

RXHCC148

Mild or Unspecified Intellectual Disability/Developmental Disorder

Coding notes

Excludes 1 never coded together · Excludes 2 may co-exist

This code · Q99.2
Synonyms

Fragile X syndrome

Inherited from Q90-Q99Chromosomal abnormalities, not elsewhere classified
Excludes 2

mitochondrial metabolic disorders (E88.4-)

Inherited from chapter 17Congenital malformations, deformations and chromosomal abnormalities
Excludes 2

inborn errors of metabolism (E70-E88)

Note

Codes from this chapter are not for use on maternal records

Official Guidelines for Q99.2

FY 2026 ›
I.C.17Chapter-specific guidanceChapter 17: Congenital malformations, deformations, and chromosomal abnormalities (Q00-QA1)

Sections that reference Q99.2

Sections whose FY 2026 text names Q99.2, its Q99 category, or a range containing it — the chapter guidance above is the authoritative source.

Find Q99.2 in the alphabetic index

2 index paths lead to this code