Zimmermann-Laband Syndrome
Zimmermann-Laband Syndrome (ZLS)
Zimmermann-Laband syndrome is a rare genetic disorder characterized by gingival fibromatosis, distinctive facial features, and abnormalities of the hands and feet. Also known as Laband syndrome or Zimmermann-Laband-Imhof syndrome.
Key Points
- Inheritance Pattern: Autosomal dominant
- Primary Genes: KCNH1, ATP6V1B2, and KCNH2
- Age of Onset: Usually evident in early infancy or early childhood
- Prevalence: Extremely rare, with fewer than 50 cases reported in medical literature
Clinical Manifestations
Oral Features
- Progressive gingival hyperplasia beginning in early childhood
- Enlargement of maxillary and mandibular gingiva
- Delayed tooth eruption or abnormal dentition
- Malocclusion and high-arched palate
Craniofacial Features
- Coarse facial features with characteristic soft tissue enlargement
- Thick lips and broad nasal tip
- Enlarged bridge of nose
- Heavy eyebrows and long eyelashes
Skeletal Abnormalities
- Hypoplastic or absent nails (particularly terminal phalanges)
- Enlarged joints, especially in fingers and toes
- Hyperextensible joints
- Hepatosplenomegaly in some cases
Neurological Features
- Intellectual disability (variable severity)
- Seizures in approximately 25% of cases
- Hypotonia in infancy
Diagnosis and Management
Diagnostic Criteria
- Clinical examination of characteristic features
- Genetic testing for KCNH1, ATP6V1B2, and KCNH2 mutations
- Family history assessment
- Radiographic evaluation of skeletal features
Management Approach
- Multidisciplinary team involvement including pediatric dentist, orthodontist, plastic surgeon, and geneticist
- Regular dental care and periodontal maintenance
- Surgical management of gingival hyperplasia when necessary
- Anticonvulsant therapy for patients with seizures
- Physical therapy for joint problems
- Regular developmental assessment and appropriate interventions
Monitoring Requirements
- Regular dental evaluation every 3-6 months
- Annual neurological assessment
- Growth and development monitoring
- Regular assessment of joint mobility and function
Genetic Basis and Inheritance
Molecular Genetics
- KCNH1 gene mutations: Most common cause (ZLS1)
- ATP6V1B2 gene mutations: Second variant (ZLS2)
- KCNH2 gene mutations: Recently identified variant (ZLS3)
Inheritance Pattern
Autosomal dominant inheritance with high penetrance but variable expressivity. New mutations account for some cases with no family history.
Genetic Counseling
- 50% chance of transmission to offspring
- Prenatal testing available for known familial mutations
- Importance of genetic counseling for family planning