Summary about Disease
Knobloch syndrome type 1 is a rare genetic disorder characterized primarily by high myopia (nearsightedness), vitreoretinal degeneration (progressive deterioration of the vitreous humor and retina of the eye), and occipital encephalocele (a sac-like protrusion of the brain through an opening in the back of the skull). Other features can vary but may include skull defects, distinctive facial features, and skeletal abnormalities. It's an autosomal recessive condition, meaning both parents must carry a copy of the mutated gene for a child to be affected.
Symptoms
Eye Abnormalities:
High myopia (severe nearsightedness)
Vitreoretinal degeneration (retinal detachment, thinning of the retina, abnormalities of the vitreous)
Lens abnormalities (cataracts, lens subluxation)
Occipital Encephalocele: A sac-like protrusion containing brain tissue, spinal fluid, and/or meninges at the back of the head.
Skull Defects: Other bony defects of the skull.
Facial Features: May include a broad, short nose, widely spaced eyes (hypertelorism), a flat nasal bridge, or a long philtrum.
Skeletal Abnormalities: Scoliosis, joint hypermobility.
Developmental Delay: Possible, but not always present.
Intellectual Disability: Possible, but not always present.
Causes
Knobloch syndrome type 1 is caused by mutations in the COL18A1 gene. This gene provides instructions for making a component of collagen XVIII, a protein found in basement membranes throughout the body. Mutations in *COL18A1* disrupt the structure and function of collagen XVIII, leading to the various features of the syndrome. It is inherited in an autosomal recessive pattern.
Medicine Used
There is no specific "medicine" that cures Knobloch syndrome. Treatment focuses on managing the individual symptoms and complications:
Eye Care:
Corrective lenses for myopia.
Surgery for retinal detachment, cataracts, or lens subluxation.
Regular eye exams to monitor for progression of vitreoretinal degeneration.
Encephalocele Repair: Surgical repair of the encephalocele may be necessary, depending on its size and contents.
Physical Therapy: To manage skeletal abnormalities and improve mobility.
Occupational Therapy: To assist with daily living skills.
Developmental Therapies: Early intervention programs for developmental delays or intellectual disability.
Is Communicable
No, Knobloch syndrome is not communicable. It is a genetic disorder, not an infectious disease. It cannot be spread from person to person.
Precautions
Since Knobloch syndrome is a genetic condition, there are no environmental precautions to prevent it in an already affected individual.
Genetic Counseling: For families with a history of Knobloch syndrome, genetic counseling is important to understand the risk of recurrence in future pregnancies.
Early Intervention: Early diagnosis and intervention can help manage symptoms and improve quality of life.
Regular Monitoring: Regular medical and ophthalmological evaluations are crucial to monitor for complications and adjust treatment as needed.
Protective Gear: Use protective eye gear, when playing sports or doing tasks that could injure the eye.
How long does an outbreak last?
Knobloch syndrome is not an infectious disease, so the term "outbreak" is not applicable. It is a lifelong genetic condition. Symptoms and their severity can change over time, requiring ongoing management.
How is it diagnosed?
Diagnosis of Knobloch syndrome typically involves:
Clinical Evaluation: Assessment of the individual's symptoms and physical examination findings, particularly the presence of ocular abnormalities and occipital encephalocele.
Ophthalmological Examination: Comprehensive eye exam to assess the extent of myopia, vitreoretinal degeneration, and other ocular features.
Neuroimaging: MRI or CT scans to evaluate the encephalocele and any other brain abnormalities.
Genetic Testing: Confirmation of the diagnosis is typically achieved through genetic testing of the COL18A1 gene.
Timeline of Symptoms
The timeline of symptoms can vary, but generally:
At Birth: Occipital encephalocele may be present at birth. High myopia and vitreoretinal degeneration may be evident early in infancy or childhood.
Infancy/Childhood: Myopia progresses, and retinal problems develop. Developmental delays may become apparent.
Throughout Life: Ocular complications may worsen over time, potentially leading to vision loss. Skeletal abnormalities may progress.
Important Considerations
Variability: The severity of Knobloch syndrome can vary significantly between individuals, even within the same family.
Multidisciplinary Care: Management requires a multidisciplinary approach involving ophthalmologists, neurosurgeons, geneticists, developmental specialists, and other healthcare professionals.
Family Support: Support groups and resources for families affected by rare genetic disorders can be beneficial.
Vision Loss: Significant vision loss is a common complication; therefore, early and ongoing ophthalmological care is essential.
Genetic Counseling: Genetic counseling is vital for families to understand the inheritance pattern and recurrence risks.