Genetic variant

rs1556423844 a variant in the MT-ND4L gene

rs1556423844 is a single-letter difference in the MT-ND4L gene, on chromosome MT. ClinVar, the public archive of variant interpretations, lists it as likely pathogenic: probably able to cause or contribute to disease. It has been reported in connection with Leber optic atrophy and Mitochondrial disease. Carrying it does not, on its own, mean you have or will develop any condition.

ClinVar: Likely pathogenic
Health Risk
Chromosome MT

What is this?

Your DNA is a long sequence of four letters. At a few million positions, people commonly differ by a single letter; each of those positions is called a SNP (“snip”), and rs1556423844 is the catalogue number of one of them, in the MT-ND4L gene. Which letters you carry there — one copy from each parent — is your genotype.

MT-ND4L (mitochondrially encoded NADH:ubiquinone oxidoreductase core subunit 4L): Enables NADH dehydrogenase (ubiquinone) activity. Predicted to be involved in mitochondrial electron transport, NADH to ubiquinone and proton motive force-driven mitochondrial ATP synthesis. Located in mitochondrial inner membrane. Part of respiratory chain complex I. Implicated in Leber hereditary optic neuropathy and diabetes mellitus. [provided by Alliance of Genome Resources, Jul 2025]
Gene description from NCBI Gene

Why might it matter?

ClinVar records this variant as likely pathogenic, meaning probably able to cause or contribute to disease. A classification describes the variant, not you: what it means for one person depends on their genotype, their family history and often on other genes and circumstances.

Conditions it has been reported with

Listed in ClinVar submissions for this variant. Being listed is a report of an association, not a statement that the variant causes the condition in any given person.

Do I have this variant?

If you have taken a consumer DNA test (23andMe, AncestryDNA and similar), you can download its raw data file and check. Create a free account, upload the file, and this page will show the letters you carry at rs1556423844, if your test read this position.

Connect this with your blood results

A gene is a fixed instruction; a blood test shows what your body is doing now. CheckMyBloods reads the two side by side, so a variant can be set against the markers it could plausibly affect.

Blood markers do not diagnose a genetic condition, and a variant does not explain a blood result on its own. Together, with symptoms and family history, they give a clinician context.

Upload blood results

What should I do next?

Find out whether you carry it. Reading about a variant says nothing about you until you know your genotype.
Put it in context. Add your blood results, so the variant can be read against what your body is doing.
Ask questions. Dr. Hemsworth, our AI assistant, can explain this variant and your results in plain English.
Take anything that worries you to a professional. A GP or genetic counsellor can order a confirmatory test and interpret it with your history.

This page is general information drawn from public research databases. It cannot diagnose anything, and it is not a substitute for advice from a doctor or genetic counsellor who knows your history.

Technical details

dbSNP ID: rs1556423844
Gene: MT-ND4L
Position: chrMT:10663
ClinVar classification: Likely pathogenic

Sources

dbSNP: rs1556423844 — the reference record
ClinVar — clinical interpretations submitted by laboratories
SNPedia — community-written summaries
NCBI Gene: MT-ND4L
Ensembl: MT-ND4L