Summary about Disease
Knobloch syndrome is a rare genetic disorder characterized by high myopia (nearsightedness), vitreoretinal degeneration (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 include skull defects, skin abnormalities, and intellectual disability in some cases. The severity of symptoms varies significantly among affected individuals.
Symptoms
Ocular: High myopia, retinal detachment, vitreous abnormalities (liquefaction, strands, membranes), lens dislocation, cataracts.
Cranial: Occipital encephalocele (ranging in size), skull defects (parietal foramina).
Skin: Cutis aplasia (absence of skin, often on the scalp), skin laxity.
Neurological: Developmental delays, intellectual disability (variable).
Other: Hypertelorism (widely spaced eyes), cleft lip/palate (rare), heart defects (rare).
Causes
Knobloch syndrome is caused by mutations in the COL18A1 gene. This gene provides instructions for making a type of collagen (collagen XVIII) found in various tissues, including the eye, brain, and skin. Mutations in this gene disrupt the production or function of collagen XVIII, leading to the characteristic features of the syndrome. It is inherited in an autosomal recessive pattern, meaning both parents must carry a copy of the mutated gene for a child to be affected.
Medicine Used
There is no specific cure for Knobloch syndrome. Treatment focuses on managing the individual symptoms:
Ophthalmological: Corrective lenses for myopia, surgery for retinal detachment, cataract removal.
Surgical: Repair of encephalocele, closure of skull defects.
Therapy: Physical therapy, occupational therapy, speech therapy for developmental delays.
Medications: Medications to manage any related cardiac or other organ system issues.
Is Communicable
No, Knobloch syndrome is not communicable. It is a genetic disorder caused by a gene mutation and cannot be spread from person to person.
Precautions
Genetic counseling: For families with a history of Knobloch syndrome.
Regular eye exams: Early and frequent eye exams are crucial for managing and treating ocular complications, such as retinal detachment.
Developmental monitoring: Early intervention programs to address developmental delays.
Protection of encephalocele: If an encephalocele is present, precautions should be taken to protect it from injury.
How long does an outbreak last?
Knobloch syndrome is not an infectious disease and does not involve outbreaks. It is a chronic genetic condition that is present from birth and lasts throughout a person's life.
How is it diagnosed?
Diagnosis is typically based on:
Clinical evaluation: Physical examination and assessment of characteristic features (high myopia, retinal abnormalities, encephalocele).
Ophthalmological examination: Detailed eye exam to identify retinal detachment, vitreous abnormalities, and other ocular features.
Neuroimaging: MRI or CT scan to visualize the encephalocele and any associated brain abnormalities.
Genetic testing: Confirmation of the diagnosis through genetic testing to identify mutations in the COL18A1 gene.
Timeline of Symptoms
At birth: Encephalocele may be present. Cutis aplasia (if present) may be visible.
Infancy/Early Childhood: High myopia is often detected. Retinal detachment can occur early. Developmental delays may become apparent.
Childhood/Adolescence: Progressive visual impairment. Risk of retinal detachment continues.
Lifelong: Management of visual impairment, developmental issues, and any other associated medical problems.
Important Considerations
Variability: The severity of symptoms can vary greatly among individuals with Knobloch syndrome.
Multidisciplinary care: Management requires a team of specialists, including ophthalmologists, neurosurgeons, geneticists, and developmental pediatricians.
Prognosis: The prognosis depends on the severity of the condition and the extent of neurological involvement. Visual impairment is often significant.
Research: Ongoing research aims to better understand the mechanisms of the disease and develop new treatments.