Overview
Micro syndrome (also known as Warburg Micro syndrome) is a rare autosomal recessive neurodevelopmental disorder characterized by microcephaly, microcornea, congenital cataracts, microphthalmia, optic atrophy, cortical visual impairment, and intellectual disability. The condition was first described by Warburg and colleagues and belongs to a spectrum of disorders sometimes referred to as the Warburg Micro syndrome–Martsolf syndrome spectrum. The syndrome primarily affects the brain, eyes, and reproductive system. Neurological features include severe intellectual disability, progressive spasticity, and structural brain abnormalities such as polymicrogyria, hypoplasia of the corpus callosum, and cerebellar hypoplasia. Affected individuals typically have profound developmental delay and may never achieve independent ambulation or speech. The eye abnormalities are among the most distinctive features and are usually present at birth, including bilateral congenital cataracts, microcornea, and progressive optic atrophy leading to significant visual impairment. Hypogonadism is another hallmark, with affected males often presenting with micropenis and cryptorchidism, while females may show hypoplastic labia minora. Affected individuals may also exhibit characteristic facial features including a prominent nasal root and anteverted nares. Micro syndrome is caused by biallelic pathogenic variants in one of several genes involved in intracellular vesicle trafficking: RAB3GAP1 (most common), RAB3GAP2, RAB18, or TBC1D20. These genes encode components of the RAB18 pathway, which plays a critical role in membrane trafficking in neurons and other cell types. There is currently no cure or disease-specific treatment for Micro syndrome. Management is supportive and multidisciplinary, involving ophthalmologic care (including early cataract surgery), physical therapy for spasticity, management of seizures if present, and developmental support. Prognosis is generally poor, with significant lifelong disability.
Also known as:
Clinical phenotype terms— hover any for plain English:
Autosomal recessive
Passed on when both parents carry the same gene change; often skips generations
Neonatal
Begins at or shortly after birth (first 4 weeks)
FDA & Trial Timeline
7 eventsMclean Hospital — NA
Central Hospital, Nancy, France
Hospices Civils de Lyon
Sarah Schiebler — NA
Helsinki University Central Hospital — NA
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Micro syndrome.
View clinical trials →Clinical Trials
View all trials with filters →No actively recruiting trials found for Micro syndrome at this time.
New trials open frequently. Follow this disease to get notified.
Rare Disease Specialist
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Micro syndrome.
Community
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Start the conversation →Latest news about Micro syndrome
Disease timeline:
New recruiting trial: Evaluation of the Performance of the IDBIORIV Method in Pathogen Identification and Antibiotic Susceptibility Testing in Patients With Sepsis
A new clinical trial is recruiting patients for Micro syndrome
New recruiting trial: Effectiveness of Acceptance Commitment Therapy or Micro Breaks in Patients with Chronic Fatigue Syndrome/ Myalgic Encephalomyelitis
A new clinical trial is recruiting patients for Micro syndrome
New recruiting trial: Comparison Of iStent to Laser in Exfoliation Glaucoma Helsinki Study Group
A new clinical trial is recruiting patients for Micro syndrome
New recruiting trial: Quality of Life After Glaucoma Surgery: Evaluating the Patient Perspective Across Surgical Options
A new clinical trial is recruiting patients for Micro syndrome
New recruiting trial: The Early Warning System for the Diabetic Encephalopathy
A new clinical trial is recruiting patients for Micro syndrome
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Common questions about Micro syndrome
What is Micro syndrome?
Micro syndrome (also known as Warburg Micro syndrome) is a rare autosomal recessive neurodevelopmental disorder characterized by microcephaly, microcornea, congenital cataracts, microphthalmia, optic atrophy, cortical visual impairment, and intellectual disability. The condition was first described by Warburg and colleagues and belongs to a spectrum of disorders sometimes referred to as the Warburg Micro syndrome–Martsolf syndrome spectrum. The syndrome primarily affects the brain, eyes, and reproductive system. Neurological features include severe intellectual disability, progressive spastici
How is Micro syndrome inherited?
Micro syndrome follows a autosomal recessive inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Micro syndrome typically begin?
Typical onset of Micro syndrome is neonatal. Age of onset can vary across affected individuals.
Which specialists treat Micro syndrome?
25 specialists and care centers treating Micro syndrome are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.