Last updated:
07/17/2025
Years published: 2025
NORD gratefully acknowledges Julia J. An, MD Candidate, Icahn School of Medicine at Mount Sinai and Patricia I. Dickson, MD, Professor of Genetics and Chief of the Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine in St. Louis, for the preparation of this report.
Summary
Congenital deafness with labyrinthine aplasia, microtia, and microdontia, also called LAMM syndrome, is a rare genetic condition that affects hearing, ear development and tooth formation.1 People with this condition are born with hearing loss, small ears (microtia) and small teeth. Most affected people do not have the inner ear structures which affect both hearing and balance.2 People with LAMM syndrome have normal growth, development and intelligence.1
LAMM syndrome is caused by changes (variants) in the FGF3 gene. Inheritance is autosomal recessive.
There is no cure yet. Treatment focuses on managing the specific symptoms.
Signs and symptoms of LAMM syndrome may include:1,2
Affected people usually have normal growth and physical development. Cognitive function is average or above average and many people thrive in educational settings for the hearing impaired. There may be some brain abnormalities in imaging exams, but these do not result in any symptoms.
There is a normal life expectancy. Healthy adults have been reported into their 40s and 50s.
LAMM syndrome is caused by changes (variants) in the FGF3 gene. The FGF3 gene gives the body instructions to make (codify) a protein called fibroblast growth factor 3 (FGF3). This protein is very important for guiding cell growth and development. Before birth, FGF3 helps cells form parts of the inner ear and it also plays a role in the development of the outer ears, teeth and other organs.1,2,3
Inheritance
LAMM syndrome is inherited in an autosomal recessive pattern.1,2 Recessive genetic disorders occur when a person inherits a disease-causing gene variant from each parent. If a person receives one normal gene and one disease-causing gene variant, this person will be a carrier for the disease but usually will not show symptoms. The risk for two carrier parents to both pass the gene variant and have an affected child is 25% with each pregnancy. The risk of having a child who is a carrier like the parents is 50% with each pregnancy. The chance for a child to receive normal genes from both parents is 25%. The risk is the same for males and females.
LAMM syndrome is extremely rare. Only around 60 individuals from over 20 unrelated families have been identified worldwide.1 This condition affects males and females equally.
Doctors may suspect the diagnosis of LAMM syndrome through a physical exam, hearing tests and CT scan or MRI scan of the inner ear. A diagnosis is confirmed with genetic testing that shows two disease-causing variants in the FGF3 gene.1,3
There is no cure for LAMM syndrome. Treatment focuses on support and management and may include:1
Management requires a team of specialists who should work together in a coordinated way. The specialists may include an ENT (ear, nose and throat doctor) with experience in treating hearing problems in young children, an audiologist who tests hearing and recommends treatment options like hearing aids, a geneticist to look at any inherited causes of hearing loss and for genetic counseling, a pediatrician who oversees the child’s overall health, a neurologist (brain and nervous system doctor) and an ophthalmologist (eye doctor) to treat vision problems.
Because of balance problems (from inner ear issues), children may have delays in walking or coordination and are more likely to fall or get hurt. Safety tips include using visual or vibrating alarms at home and school, teaching children and caregivers how to prevent injuries and using crosswalks with visual signals to reduce the risk of being hit by cars.
Recommended regular check-ups may include an annual visit to an ENT, an ophthalmologist and the full care team. Regular dental visits are also recommended.
It is important to avoid loud noise as it can damage any remaining hearing. If swimming, extra care is needed, as some children may feel very disoriented in water.
Information on current clinical trials is posted on the Internet at https://clinicaltrials.gov/. All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.
For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:
Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: [email protected]
Some current clinical trials also are posted on the following page on the NORD website:
https://rarediseases.org/living-with-a-rare-disease/find-clinical-trials/
For information about clinical trials sponsored by private sources, contact:
https://www.centerwatch.com/
For information about clinical trials conducted in Europe, contact:
https://www.clinicaltrialsregister.eu/
NORD strives to open new assistance programs as funding allows. If we don’t have a program for you now, please continue to check back with us.
NORD and MedicAlert Foundation have teamed up on a new program to provide protection to rare disease patients in emergency situations.
Learn more https://rarediseases.org/patient-assistance-programs/medicalert-assistance-program/Ensuring that patients and caregivers are armed with the tools they need to live their best lives while managing their rare condition is a vital part of NORD’s mission.
Learn more https://rarediseases.org/patient-assistance-programs/rare-disease-educational-support/This first-of-its-kind assistance program is designed for caregivers of a child or adult diagnosed with a rare disorder.
Learn more https://rarediseases.org/patient-assistance-programs/caregiver-respite/No patient organizations found related to this disease state.
The information provided on this page is for informational purposes only. The National Organization for Rare Disorders (NORD) does not endorse the information presented. The content has been gathered in partnership with the MONDO Disease Ontology. Please consult with a healthcare professional for medical advice and treatment.
The Genetic and Rare Diseases Information Center (GARD) has information and resources for patients, caregivers, and families that may be helpful before and after diagnosis of this condition. GARD is a program of the National Center for Advancing Translational Sciences (NCATS), part of the National Institutes of Health (NIH).
View reportOrphanet has a summary about this condition that may include information on the diagnosis, care, and treatment as well as other resources. Some of the information and resources are available in languages other than English. The summary may include medical terms, so we encourage you to share and discuss this information with your doctor. Orphanet is the French National Institute for Health and Medical Research and the Health Programme of the European Union.
View reportOnline Mendelian Inheritance In Man (OMIM) has a summary of published research about this condition and includes references from the medical literature. The summary contains medical and scientific terms, so we encourage you to share and discuss this information with your doctor. OMIM is authored and edited at the McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine.
View reportGeneReviews has an article on this condition covering diagnosis, management, and inheritance. Each article is written by one or more experts on the specific disease and is reviewed by other specialists. The article contains medical and scientific terms, so we encourage you to share and discuss this information with your doctor. The GeneReviews database is managed by the University of Washington.
View reportMedlinePlus has information about this condition that may include a description, frequency, causes, inheritance, and links to more information. The information is written for the public, including patients, caregivers and families. MedlinePlus is a service of the National Library of Medicine (NLM), which is part of the National Institutes of Health (NIH).
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