G20.A1 — Parkinson's disease without dyskinesia, without mention of fluctuations

G20.A1

ICD-10 Chapter 6: Nervous System — illustrative image — Chapter 6: Diseases of the nervous system (G00–G99) — illustrative image

What this code means

Parkinson's disease is a progressive condition in which loss of dopamine-producing brain cells causes tremor, stiffness and slowness.

Also called: parkinsons disease, parkinson disease.

When this code is used

Used for Parkinson's disease without dyskinesia and without mention of fluctuations.

Where it sits in ICD-10-CM

Code G20.A1 belongs to Chapter 6: Diseases of the nervous system, which covers codes G00–G99 in the FY2027 ICD-10-CM tabular list. The official description above is copied verbatim from the CDC/NCHS FY2027 code file.

Related symptoms

Related anatomy

Brain

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Frequently asked questions

What is ICD-10-CM code G20.A1?

G20.A1 is the ICD-10-CM diagnosis code for “Parkinson's disease without dyskinesia, without mention of fluctuations”. Parkinson's disease is a progressive condition in which loss of dopamine-producing brain cells causes tremor, stiffness and slowness.

When is code G20.A1 used?

Used for Parkinson's disease without dyskinesia and without mention of fluctuations. It belongs to Chapter 6 of ICD-10-CM (Diseases of the nervous system).

This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.