Overview
Metaphyseal dysplasia-maxillary hypoplasia-brachydactyly syndrome (also known as MDMHB syndrome) is an extremely rare genetic skeletal disorder that affects bone development in several parts of the body. The condition is characterized by three main features: metaphyseal dysplasia (abnormal growth of the ends of long bones, particularly near the joints), maxillary hypoplasia (underdevelopment of the upper jaw), and brachydactyly (unusually short fingers and toes). Because the bones do not develop normally, affected individuals may have a distinctive facial appearance with a flattened midface, short stature, and limb abnormalities. The long bones, especially in the legs, may appear bowed or irregularly shaped on X-rays. Some individuals may also experience mild joint problems or limited range of motion. Because this condition is so rare, the treatment landscape is limited and primarily focused on managing symptoms rather than curing the underlying cause. Orthopedic care, dental and orthodontic management, and regular monitoring of growth and bone development are the main approaches. Genetic counseling is recommended for affected families to understand the inheritance pattern and recurrence risk. Research into this condition is ongoing but limited due to the very small number of known cases worldwide.
Key symptoms:
Short fingers and toesUnderdeveloped upper jaw giving a flat midface appearanceAbnormal growth at the ends of long bonesShort statureBowed legs or leg deformitiesDental crowding or misalignmentLimited joint movementWaddling gait or difficulty walkingMild limb shorteningFlattened nasal bridge
Autosomal dominant
Passed on from just one parent; each child has about a 50% chance of inheriting it
Childhood
Begins in childhood, roughly ages 1 to 12
Treatments
No FDA-approved treatments are currently listed for Metaphyseal dysplasia-maxillary hypoplasia-brachydacty syndrome.
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Specialists
View all specialists →No specialists are currently listed for Metaphyseal dysplasia-maxillary hypoplasia-brachydacty syndrome.
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 Metaphyseal dysplasia-maxillary hypoplasia-brachydacty syndrome.
Community
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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.
Questions for your doctor
Bring these to your next appointment
- Q1.How severe are the bone changes in my child, and are they likely to worsen with growth?,Will my child need orthopedic surgery for leg bowing or other bone deformities?,When should we start orthodontic or jaw-related treatment?,Is genetic testing recommended for our family, and what would it tell us?,What is the chance of passing this condition to future children?,Are there any physical activities my child should avoid?,How often should we schedule follow-up imaging and specialist visits?
Common questions about Metaphyseal dysplasia-maxillary hypoplasia-brachydacty syndrome
What is Metaphyseal dysplasia-maxillary hypoplasia-brachydacty syndrome?
Metaphyseal dysplasia-maxillary hypoplasia-brachydactyly syndrome (also known as MDMHB syndrome) is an extremely rare genetic skeletal disorder that affects bone development in several parts of the body. The condition is characterized by three main features: metaphyseal dysplasia (abnormal growth of the ends of long bones, particularly near the joints), maxillary hypoplasia (underdevelopment of the upper jaw), and brachydactyly (unusually short fingers and toes). Because the bones do not develop normally, affected individuals may have a distinctive facial appearance with a flattened midface, s
How is Metaphyseal dysplasia-maxillary hypoplasia-brachydacty syndrome inherited?
Metaphyseal dysplasia-maxillary hypoplasia-brachydacty syndrome follows a autosomal dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Metaphyseal dysplasia-maxillary hypoplasia-brachydacty syndrome typically begin?
Typical onset of Metaphyseal dysplasia-maxillary hypoplasia-brachydacty syndrome is childhood. Age of onset can vary across affected individuals.