What is ICD-10 code E72.02?

E72.02 is the ICD-10-CM diagnosis code for Hartnup's disease. A rare inherited disorder affecting the absorption of certain amino acids in the intestines and kidneys, causing neurological symptoms, skin problems, and diarrhea. It belongs to the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89). E72.02 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. E72.02 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. E72.02 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. E72.02 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

Which HCC does E72.02 map to under V28?

E72.02 has no payable CMS-HCC V28 mapping in the final FY2026 CMS file.

What RAF reference is published for E72.02?

E72.02 has no V28 reference coefficient because the final FY2026 source verifies no payable V28 mapping.

What is the V28 vs V24 difference for E72.02?

E72.02 has verified no payable V28 mapping in the final FY2026 source. Select a historical effective period before making any V24 comparison.

What documentation supports E72.02?

Named after the physician who first described it; ensure documentation confirms this specific diagnosis Often presents with photosensitive dermatitis and neuropsychiatric symptoms E72.02 is not a CMS-HCC V28 payment code in the verified current source, so MEAT is not the payment hook. Documentation still has to support the diagnosis if you report it.

Can E72.02 be a primary diagnosis?

Yes. E72.02 carries no code-first instruction in the FY2026 tabular, so it can be the first-listed diagnosis when it is the condition chiefly responsible for the encounter and the note supports it, and it can also be reported as a secondary diagnosis. For risk adjustment the order does not matter; the V28 category is the same either way.

Which codes cannot be reported with E72.02?

The Excludes1 note that applies to E72.02 lists transitory endocrine and metabolic disorders specific to newborn (P70-P74); androgen insensitivity syndrome (E34.5-); congenital adrenal hyperplasia (E25.0); hemolytic anemias attributable to enzyme disorders (D55.-); and 8 more (see the notes on this page). An Excludes1 condition is not reported together with E72.02; report one or the other, unless the two conditions are unrelated, which the ICD-10-CM Official Guidelines (Section I.A.12.a) allow. The Excludes2 note lists Ehlers-Danlos syndromes (Q79.6-); those are separate conditions that may be reported together with E72.02 when both are documented.

2026 ICD-10-CM E72.02: Hartnup's disease

E72.02 is not a CMS-HCC payment code. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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Code lookupE72.02

Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Endocrine, nutritional and metabolic diseases (E00-E89) / Metabolic disorders (E70-E88)

E72.02

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Hartnup's disease

A rare inherited disorder affecting the absorption of certain amino acids in the intestines and kidneys, causing neurological symptoms, skin problems, and diarrhea.

Buddy Insight

Hartnup disease is an autosomal recessive disorder of neutral amino acid transport in the kidneys and intestines, caused by mutations in the SLC6A19 gene.

Overview Risk Models Code Book Documentation Audit Notes Edition comparison

CMS-HCC V28

N/A

—

Not risk-adjusted for this model/period.

Not mapped

CMS-HCC V24

Historical

Not used for standard CY2026 Medicare Advantage payment. Select a historical period to review V24.

Not used for CY2026 payment

ACA/HHS

Context needed

HCC 028

Conditional HHS-HCC mapping: HCC 028 when age < 21. Select the member context before showing a coefficient reference. Metal level and model segment are required for coefficients; no single RAF is shown.

Coefficient needs member context

ESRD/PACE

Context needed

HCC 23

ESRD candidates: HCC 23 when age < 21 or age >= 21. ESRD mapping is separate from PACE. Dialysis, graft, age, and other member context determine the applicable coefficient.

Coefficient needs member context

RXHCC

Mapped

HCC 43

Pituitary, Adrenal Gland, and...

Code-level coefficient reference

Code Book Path

Official

E72Other disorders of amino-acid metabolism E72.0Disorders of amino-acid transport E72.02Hartnup's disease

Inclusion Terms

Official

No inclusion terms are included in this display for E72.02. Check the code and parent instructions in the Code Book.

Excludes 2

Official

Ehlers-Danlos syndromes (Q79.6-)Inherited from E70-E88

Related Codes

Official

E72.00Disorders of amino-acid transport, unspecified E72.01Cystinuria E72.03Lowe's syndrome E72.04Cystinosis E72.09Other disorders of amino-acid transport

Includes

Official

No Includes notes are included in this display for E72.02. Check the code and parent instructions in the Code Book.

Excludes 1

Official

transitory endocrine and metabolic disorders specific to newborn (P70-P74)Inherited from E00-E89, E70-E88, E72, E72.0
androgen insensitivity syndrome (E34.5-)Inherited from E00-E89, E70-E88, E72, E72.0
congenital adrenal hyperplasia (E25.0)Inherited from E00-E89, E70-E88, E72, E72.0
hemolytic anemias attributable to enzyme disorders (D55.-)Inherited from E00-E89, E70-E88, E72, E72.0
Marfan syndrome (Q87.4-)Inherited from E00-E89, E70-E88, E72, E72.0
5-alpha-reductase deficiency (E29.1)Inherited from E00-E89, E70-E88, E72, E72.0
disorders of:Inherited from E00-E89, E70-E88, E72, E72.0
aromatic amino-acid metabolism (E70.-)Inherited from E00-E89, E70-E88, E72, E72.0
branched-chain amino-acid metabolism (E71.0-E71.2)Inherited from E00-E89, E70-E88, E72, E72.0
fatty-acid metabolism (E71.3)Inherited from E00-E89, E70-E88, E72, E72.0
purine and pyrimidine metabolism (E79.-)Inherited from E00-E89, E70-E88, E72, E72.0
gout (M1A.-, M10.-)Inherited from E00-E89, E70-E88, E72, E72.0
disorders of tryptophan metabolism (E70.5)Inherited from E00-E89, E70-E88, E72, E72.0

Code First

Official

No Code First sequencing instructions are included in this display for E72.02. Check the code and parent instructions in the Code Book.

Use Additional

Official

No Use Additional Code instructions are included in this display for E72.02. Check the code and parent instructions in the Code Book.

Code Also

Official

No Code Also instructions are included in this display for E72.02. Check the code and parent instructions in the Code Book.

Buddy Documentation Tip

HCC Buddy guidance

Document urine amino acid analysis showing generalized neutral aminoaciduria, clinical symptoms if present (dermatitis, ataxia, psychiatric changes), genetic testing results, nutritional status assessment, and nicotinamide supplementation regimen.

Record any triggering factors such as illness, poor nutrition, or sun exposure.

MEAT Support

HCC Buddy guidance

Record any triggering factors such as illness, poor nutrition, or sun exposure.

Audit Caution

HCC Buddy guidance

Do not confuse Hartnup disease with dietary pellagra (niacin deficiency).

The biochemical urine profile distinguishes the two conditions.

Many patients identified through newborn screening remain asymptomatic and may not require active coding unless clinically significant.

Common Mistakes

HCC Buddy guidance

E52 (Niacin deficiency

pellagra) which presents with similar skin and neurological findings but has dietary rather than genetic etiology; E72.00 (Disorders of amino-acid transport, unspecified) which lacks specificity; E72.09 (Other disorders of amino-acid transport) for transport disorders not specifically coded.

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is E72.02 an HCC code?

E72.02 is not in the CMS-HCC V28 or V24 community payment model. E72.02 has a separate mapping under the CMS-HCC ESRD model (HCC 23 (Other Significant Endocrine and Metabolic Disorders)) and the Part D RxHCC model (HCC 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders)); the applicable result needs member context. E72.02 also appears in the HHS-HCC commercial risk model (HCC 028 (HHS-HCC 028 child, RAF varies by metal level)), where the result depends on member context and is not a Medicare Advantage payment mapping.

Code: E72.02
Description: Hartnup's disease
HCC (V28): No CMS-HCC V28 mapping
RAF reference coefficient: —
Billable: Yes
Payment year: 2026

HCC Category Mapping

RxHCCHCC 43, Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders

Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work E72.02 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT review for E72.02

For E72.02, confirm that the documentation supports the diagnosis and meets the applicable coding, encounter, program and payer requirements. MEAT (Monitor, Evaluate, Assess, or Treat) is a review mnemonic, not a universal CMS coding rule.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Coder workflow notes

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What This Code Means

E72.02 is the ICD-10-CM diagnosis code for hartnup's disease. A rare inherited disorder affecting the absorption of certain amino acids in the intestines and kidneys, causing neurological symptoms, skin problems, and diarrhea. E72.02 sits in the ICD-10-CM chapter for endocrine, nutritional and metabolic diseases (e00-e89), within the section covering metabolic disorders (e70-e88).

E72.02 has no mapping under the CMS-HCC V28 or V24 community payment models. E72.02 has a separate mapping under the CMS-HCC ESRD model (HCC 23 (Other Significant Endocrine and Metabolic Disorders)) and the Part D RxHCC model (HCC 43 (Pituitary, Adrenal Gland, and Other Endocrine and Metabolic Disorders)); the applicable result needs member context. E72.02 also appears in the HHS-HCC commercial risk model (HCC 028 (HHS-HCC 028 child, RAF varies by metal level)), where the result depends on member context and is not a Medicare Advantage payment mapping. Do not assign V28 risk adjustment value from this page; verify the applicable model and payment year before using this code for risk adjustment.

Named after the physician who first described it; ensure documentation confirms this specific diagnosis.

HCC Buddy maintains structured V28 and V24 mapping, source-labeled coefficient references, and MEAT documentation criteria for E72.02 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Named after the physician who first described it; ensure documentation confirms this specific diagnosis
•Often presents with photosensitive dermatitis and neuropsychiatric symptoms

Clinical Significance

Hartnup disease is an autosomal recessive disorder of neutral amino acid transport in the kidneys and intestines, caused by mutations in the SLC6A19 gene. The resulting tryptophan malabsorption can cause pellagra-like symptoms including photosensitive dermatitis, cerebellar ataxia, and psychiatric manifestations during metabolic stress. Most affected individuals remain asymptomatic with adequate nutrition, and nicotinamide supplementation effectively prevents symptoms.

Documentation Requirements

✓Document urine amino acid analysis showing generalized neutral aminoaciduria, clinical symptoms if present (dermatitis, ataxia, psychiatric changes), genetic testing results, nutritional status assessment, and nicotinamide supplementation regimen.
✓Record any triggering factors such as illness, poor nutrition, or sun exposure.

Commonly Confused Codes

•E52 (Niacin deficiency
•pellagra) which presents with similar skin and neurological findings but has dietary rather than genetic etiology; E72.00 (Disorders of amino-acid transport, unspecified) which lacks specificity; E72.09 (Other disorders of amino-acid transport) for transport disorders not specifically coded.