Skip to content
Dx

ICD-10-CM 2027

ICD-10 code for XXXXY syndrome

Q98.1

Klinefelter syndrome, male with more than two X chromosomes

✓ Billable / specificMale only

From the official ICD-10-CM alphabetic index entry “Syndrome › XXXXY”. Page updated September 29, 2026.

About coding XXXXY syndrome

The ICD-10-CM code for XXXXY syndrome is Q98.1 (Klinefelter syndrome, male with more than two X chromosomes).

Within Q98 (other sex chromosome abnormalities, male phenotype, not elsewhere classified), Q98.1 is specifically for Klinefelter syndrome, male with more than two X chromosomes. Related codes cover Klinefelter syndrome karyotype 47, XXY (Q98.0), other male with 46, XX karyotype (Q98.3), Klinefelter syndrome, unspecified (Q98.4), karyotype 47, XYY (Q98.5), male with structurally abnormal sex chromosome (Q98.6), male with sex chromosome mosaicism (Q98.7), other specified sex chromosome abnormalities, male phenotype (Q98.8) and sex chromosome abnormality, male phenotype, unspecified (Q98.9).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 729 (Other Male Reproductive System Diagnoses with CC/MCC, relative weight 1.0544) and DRG 730 (Other Male Reproductive System Diagnoses without CC/MCC, relative weight 0.6597), in MDC 12 (Diseases and Disorders of the Male Reproductive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

Common questions about XXXXY syndrome ICD-10 codes

What is the ICD-10 code for XXXXY syndrome?

Q98.1 — Klinefelter syndrome, male with more than two X chromosomes.

Is Q98.1 billable?

Yes. Q98.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).

Can Q98.1 be used as a principal diagnosis?

Yes. The Medicare Code Editor doesn't restrict Q98.1 as a principal diagnosis.

Is Q98.1 a CC or MCC?

No. Q98.1 is neither a CC nor an MCC under MS-DRG v44.0.