ICD10 code of Allan-Herndon-Dudley Syndrome and ICD9 code

Allan-Herndon-Dudley syndrome does not have a unique, specific code in the ICD-10 or ICD-9 systems; instead, clinicians typically use codes for related manifestations or unspecified X-linked intellectual disability. Because Allan-Herndon-Dudley syndrome is an extremely rare condition, it is often coded under broader categories like E07.89 (other specified disorders of thyroid) or Q79.8 (other congenital malformations) depending on the clinical focus.

Why is there no specific ICD code for Allan-Herndon-Dudley syndrome?

The lack of a dedicated ICD-10 or ICD-9 code for Allan-Herndon-Dudley syndrome is common for rare diseases that represent a specific genetic mutation rather than a broad diagnostic category. Clinicians often use the ICD-10 code Q79.8 or G40, or they may utilize the code E07.89 to reflect the underlying thyroid hormone transporter defect. Currently, 8 members of the DiseaseMaps.org community living with Allan-Herndon-Dudley syndrome share insights on navigating these coding challenges during insurance and clinical documentation processes.

What clinical features define Allan-Herndon-Dudley syndrome?

Allan-Herndon-Dudley syndrome is a rare X-linked condition characterized by severe intellectual disability and significant motor impairment. The condition arises from mutations in the SLC16A2 gene, which encodes the MCT8 thyroid hormone transporter. Key clinical hallmarks often include:

• Severe developmental delay and cognitive impairment


• Hypotonia (low muscle tone) in infancy, progressing to spasticity


• Limited or absent speech development


• Characteristic thyroid function test results (elevated T3, low T4, and normal or slightly elevated TSH)


• Inability to sit, stand, or walk independently

Is Allan-Herndon-Dudley syndrome hereditary?

Yes, Allan-Herndon-Dudley syndrome follows an X-linked recessive inheritance pattern. Because the gene is located on the X chromosome, it primarily affects males. Female carriers usually do not exhibit symptoms of Allan-Herndon-Dudley syndrome, though genetic counseling is essential for families to understand the 50% recurrence risk for male offspring of carrier mothers.

Next steps

• Consult with a pediatric neurologist or a clinical geneticist to confirm the SLC16A2 mutation.


• Connect with the Allan-Herndon-Dudley syndrome community on DiseaseMaps.org to share experiences with medical coding and care management.


• Request a referral to a metabolic specialist familiar with thyroid hormone transport disorders.


• Maintain a detailed medical record to help your healthcare team select the most appropriate billing codes for your specific insurance needs.

Medical disclaimer: This content is for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment; always seek the advice of your physician with any questions regarding a medical condition.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Allan-Herndon-Dudley syndrome profile.


• Orphanet: Rare Disease Database (ORPHA:99925).


• OMIM (Online Mendelian Inheritance in Man): #300523 (Allan-Herndon-Dudley syndrome).


• PubMed: Recent literature on SLC16A2-related disorders and thyroid hormone transport.