2027 ICD-10-CM Diagnosis Code F78.A1SYNGAP1-related intellectual disability

ICD-10-CM Codes›F01–F99›F70-F79›F78

ICD-10-CM F78.A1
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

F78.A1 is a billable ICD-10-CM diagnosis code for SYNGAP1-related intellectual disability. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 884. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Neurodevelopmental disorders.

F78.A1 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 147 for payment year 2027.

Code Identity

ICD-10-CM Code
F78.A1
Billable Status
Yes — Valid for Submission
Code Describes
SYNGAP1-related intellectual disability
Short Description
SYNGAP1-related intellectual disability
Same as the full description in the CMS dataset.
Parent Code
F78.A
Other genetic related intellectual disabilities

Code Classification

ChapterF01–F99Mental and behavioural disorders
SectionF70-F79Intellectual disabilities
CategoryF78Other intellectual disabilities
This CodeF78.A1SYNGAP1-related intellectual disability

Medicare Risk Adjustment (HCC)Billing

F78.A1 does not risk-adjust for Medicare Advantage under the CMS-HCC V28 model, but it maps to payment categories in the other CMS models shown below.

CMS-HCC V28 (Medicare Advantage Payment Model)
Not mapped
no payment category in the model that pays 100% of MA risk scores
Prior Model (CMS-HCC V24)
Not mapped under V24
this diagnosis newly risk-adjusts under the V28 model
Part D (RxHCC)
RxHCC 147 — Moderate Intellectual Disability/Developmental Disorder
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to F78.A1: its own notes plus those printed at block F70-F79 and Chapter 5. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Chapter 5 (F01-F99) Mental and behavioural disorders applies to 872 codes
  • disorders of psychological development

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From Block F70-F79 Intellectual disabilities applies to 7 codes
  • borderline intellectual functioning, IQ above 70 to 84 (R41.83)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From Chapter 5 (F01-F99) Mental and behavioural disorders applies to 872 codes
  • symptoms, signs and abnormal clinical laboratory findings, not elsewhere classified (R00-R99)

Code First

The underlying condition named in the note is sequenced before this code.

From Block F70-F79 Intellectual disabilities applies to 7 codes
  • any associated physical or developmental disorders

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

  • 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)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name F78.A1, its category, or a range that includes it.

Applicable To 1

These notes mention F78.A1.

  • Z81.0 Family history of intellectual disabilities
    Conditions classifiable to F70-F79 names F70-F79, which includes this code

Excludes1 1

These codes carry an Excludes1 note naming F78.A1: they are not reported together with it, unless the two conditions are unrelated.

  • R41.83 Borderline intellectual functioning
    intellectual disabilities (F70-F79) names F70-F79, which includes this code

Excludes2 4

These codes carry an Excludes2 note naming F78.A1: its condition is not part of those codes, and both may be reported when the patient has both.

  • F80.0 Phonological disorder
    speech articulation impairment due to intellectual disabilities (F70-F79) names F70-F79, which includes this code
  • F80.1 Expressive language disorder
    intellectual disabilities (F70-F79) names F70-F79, which includes this code
  • F80.2 Mixed receptive-expressive language disorder
    intellectual disabilities (F70-F79) names F70-F79, which includes this code
  • F82 Specific developmental disorder of motor function
    lack of coordination secondary to intellectual disabilities (F70-F79) names F70-F79, which includes this code

Code First 1

These codes say to code first a condition named in the note, and F78.A1 is one of the conditions named.

  • Z91.83 Wandering in diseases classified elsewhere
    intellectual disabilities (F70-F79) names F70-F79, which includes this code

Use Additional Code 5

These codes say to use an additional code from the note, and F78.A1 is one of the codes named.

  • E00 Congenital iodine-deficiency syndrome
    code (F70-F79) to identify associated intellectual disabilities. names F70-F79, which includes this code
  • Q87.87 Hao-Fountain Syndrome
    intellectual disabilities (F70-F79) names F70-F79, which includes this code
  • Q87.88 CTNNB1 syndrome
    intellectual disability (F70-F79) names F70-F79, which includes this code
  • Q90 Down syndrome
    code(s) to identify any associated degree of intellectual disabilities (F70-F79) names F70-F79, which includes this code
  • Q93.52 Phelan-McDermid syndrome
    degree of intellectual disabilities (F70-F79) names F70-F79, which includes this code

Code Also 4

These codes say F78.A1 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • G93.45 Developmental and epileptic encephalopathy
    intellectual disabilities (F70-F79) names F70-F79, which includes this code
  • Q87.85 MED13L syndrome
    intellectual disability (F70-F79) names F70-F79, which includes this code
  • QA0 Neurodevelopmental disorders related to specific genetic pathogenic variants
    intellectual disabilities (F70-F79) names F70-F79, which includes this code
  • Z15.1 Genetic susceptibility to epilepsy and neurodevelopmental disorders
    intellectual disabilities (F70-F79) names F70-F79, which includes this code

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

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

CCSR MBD014
Neurodevelopmental disorders
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Developmental Disabilities

Developmental disabilities are conditions that are usually present at birth. They can affect a child's growth and development. These conditions can cause physical, learning, language, or behavior issues. They can include:

The full article covers:

  • What are developmental disabilities?
  • What causes developmental disabilities?
  • How are developmental disabilities diagnosed?
  • What are the treatments for developmental disabilities?

Read the full article at MedlinePlus

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

Code History & ChangesHistory

Replacement F78.A1 replaces the following previously assigned code(s):

  • F78 - Other intellectual disabilities
FY 2022AddedAdded to the ICD-10-CM code setEffective October 1, 2021.
FY 2023–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About F78.A1Overview

What is the ICD-10 code for SYNGAP1-related intellectual disability?

The ICD-10-CM code for SYNGAP1-related intellectual disability is F78.A1 (sometimes written as F78A1). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is F78.A1 (Other genetic related intellectual disabilities) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report SYNGAP1-related intellectual disability on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does F78.A1 group to?

When SYNGAP1-related intellectual disability is the principal diagnosis on an inpatient stay, it groups to MS-DRG 884 (organic Disturbances and Intellectual Disability), which carries a relative weight of 1.5998. Higher weights mean higher Medicare reimbursement.

Can F78.A1 be reported with R41.83?

Not as a rule. The Excludes1 note at block F70-F79, which applies to F78.A1, lists "borderline intellectual functioning, IQ above 70 to 84 (R41.83)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

Does F78.A1 risk-adjust for Medicare Advantage payment?

Not for Medicare Advantage: F78.A1 maps to no category in the CMS-HCC V28 model. It still risk-adjusts in the RxHCC Part D (V08) category 147 (Moderate Intellectual Disability/Developmental Disorder).