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F78.A1 ICD-10-CM Code: SYNGAP1-related intellectual disability

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
1 Excludes1 · 1 code-first instruction · 7 code-also instructions
Risk adjustment
RxHCC V08 category 147

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 884 — ORGANIC DISTURBANCES AND INTELLECTUAL DISABILITY (MDC 19)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for F78.A1 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on F78.A1 itself; “inherited from” names the category or block whose note applies here.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Source: inherited from F70-F79

Code First

Underlying conditions that must be sequenced before this code.

  • any associated physical or developmental disorders

Source: inherited from F70-F79

Code Also

Additional codes that may be required to fully describe the encounter.

  • Code also, if applicable, any associated:
  • autism spectrum disorder (F84.0)
  • autistic disorder (F84.0)
  • encephalopathy (G93.4-)
  • epilepsy and recurrent seizures (G40.-)
  • other pervasive developmental disorders (F84.8)
  • pervasive developmental disorder, NOS (F84.9)

Coder workflow for F78.A1

MedCoder structured workflow — derived from this code’s own official record

Before you code F78.A1

  1. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with F78.A1. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

    See the official tabular notes

Choose the right path

  1. Does the documentation support a condition named in F78.A1’s Excludes1 note?
    Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
    No → Continue.

    ReviewR41.83

  2. Is the underlying (etiologic) condition the Code First note names documented?
    Yes → Sequence the underlying condition first, then F78.A1.
    No → Continue; do not add an underlying condition the record does not document.

Consider F78.A1. Then review the Code Also note, and confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement
Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).
The underlying (etiologic) condition
Named in the Code First note; sequenced before this code when documented (Guidelines I.A.13).

Official instructions as workflow

  • Excludes1 — check before selecting F78.A1(1 note)

    Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with F78.A1: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

    CompareR41.83

    See the official tabular notes · Guidelines I.A.12.a

  • Code First — sequencing check(1 note)

    Coding workflow: Check whether the underlying or etiologic condition the note names is documented. When it is, sequence it before F78.A1. Do not add an underlying condition the record does not document.

    See the official tabular notes · Guidelines I.A.13

  • Code Also — related condition(7 notes)

    Coding workflow: Review the related condition when both are documented and the instruction applies. A Code Also note does not fix sequencing; the order follows the circumstances of the encounter.

    ReviewF84.0, G93.4, G40, F84.8, F84.9

    See the official tabular notes · Guidelines I.A.17

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Documentation: Both the condition F78.A1 describes and a condition named in its Excludes1 note are documented for the same encounter.

Coding question: Can both codes be reported?

Path: Review the Excludes1 note and the excluded code, and look for a provider statement on whether the two conditions are related.

Reason: Excludes1 means the two are not coded together; the exception is when the record shows the conditions are unrelated to each other (Guidelines I.A.12.a).

ReviewR41.83

Documentation: The underlying condition the Code First note names is documented alongside this condition.

Coding question: How are the two sequenced?

Path: Review the Code First note.

Reason: The underlying condition is sequenced first and the manifestation follows (Guidelines I.A.13).

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Code Overview

SYNGAP1-related intellectual disability is a billable ICD-10-CM diagnosis code (F78.A1).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

Indexed Clinical Terms (4)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

  1. Sequencing: 1 Code First instruction — the underlying condition is sequenced before this code when present. See the Code First notes
  2. 7 Code Also notes — a second code may apply; the guidelines leave its sequencing to the circumstances of the encounter. See the Code Also notes
  3. 1 Excludes1 entry — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

Other codes that name F78.A1 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 1 Excludes1 note: R41.83 — Borderline intellectual functioning (via F78.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 4 Excludes2 notes: F80.0 — Phonological disorder (via F78.-), F80.1 — Expressive language disorder (via F78.-), F80.2 — Mixed receptive-expressive language disorder (via F78.-), F82 — Specific developmental disorder of motor function (via F78.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

Referenced by 1 Code First instruction: Z91.83 — Wandering in diseases classified elsewhere (via F78.-).

Each of these codes carries a Code First note naming this condition — when that code is reported, THIS code is sequenced first, ahead of it.

Referenced by 5 Use Additional Code instructions across 2 chapters: E00 — Congenital iodine-deficiency syndrome (via F78.-), Q87.87 — Hao-Fountain Syndrome (via F78.-), Q87.88 — CTNNB1 syndrome (via F78.-), Q90 — Down syndrome (via F78.-), Q93.52 — Phelan-McDermid syndrome (via F78.-).

These codes instruct coders to additionally report this code when it applies.

Referenced by 4 Code Also instructions across 4 chapters: G93.45 — Developmental and epileptic encephalopathy (via F78.-), Q87.85 — MED13L syndrome (via F78.-), QA0 — Neurodevelopmental disorders related to specific genetic pathogenic variants (via F78.-), Z15.1 — Genetic susceptibility to epilepsy and neurodevelopmental disorders (via F78.-).

These codes suggest coding this condition alongside when both are present.

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 1 MS-DRG: DRG 884 (MDC 19).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):MBD014 — Neurodevelopmental disorders (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Neurodevelopmental disorders).

F70 — Mild intellectual disabilities, F71 — Moderate intellectual disabilities, F72 — Severe intellectual disabilities, F73 — Profound intellectual disabilities, F78 — Other intellectual disabilities, F78.A9 — Other genetic related intellectual disability, F79 — Unspecified intellectual disabilities, F80.0 — Phonological disorder, F80.1 — Expressive language disorder, F80.2 — Mixed receptive-expressive language disorder, F80.4 — Speech and language development delay due to hearing loss, F80.81 — Childhood onset fluency disorder, F80.82 — Social pragmatic communication disorder, F80.89 — Other developmental disorders of speech and language, F80.9 — Developmental disorder of speech and language, unspecified, F81.0 — Specific reading disorder, F81.2 — Mathematics disorder, F81.81 — Disorder of written expression, F81.89 — Other developmental disorders of scholastic skills, F81.9 — Developmental disorder of scholastic skills, unspecified, +24 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main term “Disability, disabilities”; these codes share that main term but sit in a different category of the Tabular List.

F70 — Mild intellectual disabilities (intellectual, mild), F71 — Moderate intellectual disabilities (intellectual, moderate), F72 — Severe intellectual disabilities (intellectual, severe), F73 — Profound intellectual disabilities (intellectual, profound), F79 — Unspecified intellectual disabilities (intellectual), F81.81 — Disorder of written expression (spelling, specific), F81.9 — Developmental disorder of scholastic skills, unspecified (learning), F84.9 — Pervasive developmental disorder, unspecified (intellectual, with, autistic features), Z73.6 — Limitation of activities due to disability (limiting activities)

Contextual Map

Every relationship of F78.A1 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Run F78.A1 with these 20 related codes in Claim Check

Hierarchy

Code Also

Referenced by Excludes1 notes

Referenced by Excludes2 notes

Referenced by Code First instructions

Referenced by Use Additional Code instructions

  • E00 — Congenital iodine-deficiency syndrome[Use Additional Code](via F78.-): “code (F70-F79) to identify associated intellectual disabilities.”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • Q87.87 — Hao-Fountain Syndrome[Use Additional Code](via F78.-): “intellectual disabilities (F70-F79)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • Q87.88 — CTNNB1 syndrome[Use Additional Code](via F78.-): “intellectual disability (F70-F79)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • Q90 — Down syndrome[Use Additional Code](via F78.-): “code(s) to identify any associated degree of intellectual disabilities (F70-F79)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • Q93.52 — Phelan-McDermid syndrome[Use Additional Code](via F78.-): “degree of intellectual disabilities (F70-F79)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Code Also instructions

Clinical classification (CCSR)

MS-DRG Grouper

MDC crossing

  • MDC 19 — Mental Diseases and Disorders[MDC crossing]: “Mental Diseases and Disorders — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

  • Disability, disabilities, intellectual, genetic related, SYNGAP1-related[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Disability, disabilities, intellectual, genetic related, with, pathogenic SYNGAP1 (variant)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Disability, disabilities, intellectual, SYNGAP1-related[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Disability, disabilities, intellectual, with, pathogenic SYNGAP1 (genetic) (variant)[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

Change history

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data
CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page
Claim edits Official source data
CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page
Inpatient payment groups Official source data
CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page
Change history and date-of-service validity Official source data
CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page
Comparisons, relationships and the contextual map MedCoder structured relationship
Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears
Summary and FAQ answers MedCoder explanation
Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "F78.A1 — SYNGAP1-related intellectual disability." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/f78.a1-syngap1-related-intellectual-disability

Change history

  • FY2022 — October 1, 2021
    Added to the code set
    SYNGAP1-related intellectual disability
    FY2022 changes

Nearest Codes in This Family

Official ICD-10-CM classifications closest to F78.A1 in its code family, with their registry titles.

View all codes in the F78 family