How is Alström syndrome diagnosed?

TL;DR: Alström syndrome is diagnosed through a combination of characteristic clinical features—most notably early-onset vision loss, obesity, and insulin resistance—confirmed by molecular genetic testing for mutations in the ALMS1 gene. Because it is a multisystem disorder, a definitive diagnosis often requires a multidisciplinary evaluation by specialists, including clinical geneticists, ophthalmologists, and endocrinologists.

How is Alström syndrome diagnosed clinically?

The diagnostic process for Alström syndrome is often a long journey, frequently referred to as a "diagnostic odyssey." Because the symptoms evolve over time, physicians often look for a specific cluster of clinical findings. The diagnosis usually begins with an ophthalmologic evaluation, as cone-rod dystrophy typically appears in infancy. As the child grows, clinicians look for the hallmark progression of Alström syndrome, which includes rapid weight gain (often starting in early childhood), sensorineural hearing loss, and signs of metabolic dysfunction like type 2 diabetes or hyperinsulinemia.

What tests are used to confirm Alström syndrome?

While clinical observation provides the initial suspicion, genetic testing is the gold standard for confirming Alström syndrome. The following examinations and tests are routinely used during the diagnostic process:

• Molecular Genetic Testing: Sequencing of the ALMS1 gene to identify biallelic pathogenic variants.


• Ophthalmological Exams: Electroretinography (ERG) to document the early-onset cone-rod dystrophy.


• Endocrinology Panels: Blood tests to measure fasting insulin, glucose, and lipid profiles to assess metabolic health.


• Audiology: Pure-tone audiometry to monitor the progression of sensorineural hearing loss.


• Imaging: Echocardiograms to screen for dilated cardiomyopathy, a serious complication of Alström syndrome.


• Liver Function Tests: Monitoring for hepatic fibrosis or steatosis, which are common manifestations.

Which specialists should be involved in the diagnosis?

Because Alström syndrome affects multiple organ systems, a single primary care physician is rarely equipped to make the diagnosis alone. A clinical geneticist is typically the coordinator of the diagnostic process. They often work in concert with a team, including pediatric ophthalmologists, endocrinologists, cardiologists, and audiologists. If you feel your current medical team is not considering this diagnosis despite the presence of these symptoms, it is vital to seek a referral to a metabolic or genetic center of excellence.

What conditions are in the differential diagnosis?

Alström syndrome is frequently misdiagnosed because its symptoms overlap with other ciliopathies. The most common differential diagnosis is Bardet-Biedl syndrome (BBS). While both conditions involve vision loss and obesity, BBS typically presents with polydactyly (extra fingers or toes) and cognitive impairment, which are generally not features of Alström syndrome. Other conditions, such as early-onset diabetes or isolated obesity, are often explored before a rare genetic diagnosis is considered, contributing to the frustration and isolation many families feel.

Next steps

• Consult with a clinical geneticist to discuss whether ALMS1 gene testing is appropriate for your symptoms.


• Gather detailed medical records, including past vision test results and blood glucose history, to present to a specialist.


• Join the DiseaseMaps.org community to connect with the 45 members who have shared their experiences with Alström syndrome.


• Visit the Alström Syndrome International foundation website for specialized resources and clinical trial information.

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

References

• Orphanet: Alström syndrome (ORPHA:65)


• NIH GARD: Alström syndrome (Genetic and Rare Diseases Information Center)


• OMIM: Alström syndrome (Entry #203800)


• Alström Syndrome International (Patient Advocacy and Support)