2026 ICD-10-CM Diagnosis Code Q79.9Congenital malformation of musculoskeletal system, unspecified

ICD-10-CM Codes›Q00-Q99›Q65-Q79›Q79

ICD-10-CM Q79.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q79.9 is a billable ICD-10-CM diagnosis code for congenital malformation of musculoskeletal system, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 564 through 566. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Musculoskeletal congenital conditions.

Code Identity

ICD-10-CM Code
Q79.9
Billable Status
Yes — Valid for Submission
Code Describes
Congenital malformation of musculoskeletal system, unspecified
Short Description
Congenital malformation of musculoskeletal system, unsp
Parent Code
Q79
Congenital malformations of musculoskeletal system, not elsewhere classified

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ65-Q79Congenital malformations and deformations of the musculoskeletal system
CategoryQ79Congenital malformations of musculoskeletal system, not elsewhere classified
This CodeQ79.9Congenital malformation of musculoskeletal system, unspecified

Present on Admission (POA)Billing

Q79.9 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • 46,XX disorder of sex development with skeletal anomalies syndrome
  • Aberrant muscle of the lower limb
  • Abnormally short long bone
  • Ambiguous genitalia
  • Angio-osteohypertrophic syndrome
  • Aplasia of bone of axial skeleton
  • Bone absent
  • Brain malformations, musculoskeletal abnormalities, facial dysmorphism, intellectual disability syndrome
  • Cerebrofacioarticular syndrome
  • CODAS syndrome
  • Combined malformation of central nervous system and skeletal muscle
  • Congenital abnormal cone shape of epiphysis with epiphyseal arrest
  • Congenital abnormal slender shape of diaphysis of long bone
  • Congenital abnormal slender shape of long bone
  • Congenital abnormal triangular shape of epiphysis
  • Congenital anomaly of abdomen
  • Congenital anomaly of bone and joint
  • Congenital anomaly of muscle AND/OR tendon
  • Congenital anomaly of musculoskeletal structure of trunk
  • Congenital anomaly of musculoskeletal system
  • Congenital anomaly of skeletal bone
  • Congenital deformity of musculoskeletal system
  • Congenital lordosis deformity of spine
  • Congenital lordosis deformity of spine due to congenital malformation of skeletal bone
  • Cyprus facial neuromusculoskeletal syndrome
  • Marfanoid habitus, facial dysmorphism, skeletal abnormality, heart defect syndrome
  • Marfanoid physique
  • Multiple bony abnormalities
  • Muscle eye brain disease
  • Nathalie syndrome
  • Neurodevelopmental disorder, craniofacial dysmorphism, cardiac defect, skeletal anomalies syndrome
  • SCARF syndrome

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Congenital anomaly of musculoskeletal system NOS
  • Congenital deformity of musculoskeletal system NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Agenesis
      • bone
    • Agenesis
      • cartilage
    • Anomaly, anomalous(congenital) (unspecified type)
      • bone
    • Anomaly, anomalous(congenital) (unspecified type)
      • bursa
    • Anomaly, anomalous(congenital) (unspecified type)
      • fascia
    • Anomaly, anomalous(congenital) (unspecified type)
      • ligament
    • Anomaly, anomalous(congenital) (unspecified type)
      • muscle
    • Anomaly, anomalous(congenital) (unspecified type)
      • musculoskeletal system, except limbs
    • Anomaly, anomalous(congenital) (unspecified type)
      • tendon
    • Deformity
      • bone (acquired) NOS
        • congenital
    • Deformity
      • bursa, congenital
    • Deformity
      • ligament (acquired)
        • congenital
    • Deformity
      • muscle (acquired)
        • congenital
    • Deformity
      • musculoskeletal system (acquired)
        • congenital
    • Development
      • abnormal, bone
    • Elongated, elongation(congenital)
      • bone
    • Fusion, fused(congenital)
      • ossicles
    • Hypoplasia, hypoplastic
      • bone NOS
    • Malformation(congenital)
      • bone
    • Malformation(congenital)
      • bursa
    • Malformation(congenital)
      • musculoskeletal system
    • Malformation(congenital)
      • tendon
    • Rudimentary(congenital)
      • bone

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MAL008
Musculoskeletal congenital conditions
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Codas Syndrome

    a rare syndrome caused by mutations in the lonp1 gene. it is characterized by developmental delay, cerebral, ocular, dental, auricular, and skeletal abnormalities.

Patient EducationClinical

Birth Defects

A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of pregnancy. One out of every 33 babies in the United States is born with a birth defect.

The full article covers:

  • What are birth defects?
  • What causes birth defects?
  • Who is at risk of having a baby with birth defects?
  • How are birth defects diagnosed?
  • What are the treatments for birth defects?
  • Can birth defects be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Q79.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
756.9 Musculoskel anom NEC/NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Q79.9Overview

Is Q79.9 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report congenital malformation of musculoskeletal system, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does Q79.9 group to?

When congenital malformation of musculoskeletal system, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 564, 565, 566, with relative weights from 0.7493 to 1.5436 depending on complications. Higher weights mean higher Medicare reimbursement.

Is Q79.9 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for congenital malformation of musculoskeletal system, unspecified on inpatient claims.

What is the ICD-9 equivalent of Q79.9?

Under the General Equivalence Mappings, congenital malformation of musculoskeletal system, unspecified converts to ICD-9-CM 756.9 (musculoskel anom NEC/NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.