[MIM 267 750]

(Knobloch-Layer syndrome)

Unknown exact prevalence but to date, less than 100 cases have been described. Autosomal recessive inheritance.

Three types have been identified:

-        type 1, the most common: mutation of the COL18A1 gene (21q22.3) mostly expressed in the eye

-        type 2: mutation of the ADAMTS18 gene (16q23.1)

-        type 3: mutation of a not yet identified gene (17q11.2)

Association of:

• early severe myopia (in the first year of life),
• vitreoretinal degeneration with retinal detachment,
• ocular abnormalities: abnormal macula, congenital cataract, iris abnormalities and subluxation of the lens, ocular albinism
• a median encephalocele (usually occipital, associated with local aplasia cutis) often accompanied by structural abnormalities of the brain. Risk of hydrocephalus, epilepsy and cognitive impairment.

Sometimes: abnormalities of the pulmonary lymphatic vessels, patent ductus arteriosus, single umbilical artery, flat nasal root, midfacial hypoplasia, bilateral epicanthus, cardiac dextroversion, hyperextensibility of the joints, abnormal palmar folds and unilateral duplication of the urinary tract. Eye lesions are severe and progressive and regularly lead to bilateral blindness.

Anesthetic implications:

associated brain abnormalities, eye protection; check: hydrocephalus and epilepsy

References : 

Updated: July 2022