Keratan sulphate excretion in a patient with Kniest dysplasia

Orthodontic Treatment in a Patient With Kniest Dysplasia: A Case Study and Review of Literature

Kniest dysplasia is a rare autosomal dominant chondrodysplasia that is characterized by distinct musculoskeletal and craniofacial irregularities. These craniofacial abnormalities include cleft palate, midface anomalies, tracheomalacia, and hearing loss. This article illustrates a case of Kniest dysplasia that presented for orthodontic treatment. The purpose of this literature review is to describe clinical manifestations, radiographic features, histopathological features, genetic mutation, and management of Kniest dysplasia.

Kniest dysplasia: Dr. W. Kniest, his patient, the molecular defect

Kniest dysplasia is a severe chondrodysplasia caused by the defective formation of type II collagen. We report about Dr. Kniest, who first described the condition in 1952, and his patient, who, at the age of 50 years is severely handicapped with short stature, restricted joint mobility, and blindness but is mentally alert and leads an active life. Molecular analysis of the patient's DNA showed a single base (G) deletion involving the GT dinucleotide at the start of intron 18 destroying a splice site of the COL2A1 gene. This is in accordance with molecular findings in other patients with Kniest dysplasia and confirms, in the original patient, that the disorder is caused by small inframe deletions often due to exon skipping as a result of COL2A1 splice site mutations.

The ocular findings in Kniest dysplasia

We studied seven patients who had Kniest dysplasia. All of the patients had congenital severe myopia and vitreoretinal degeneration. Four patients developed rhegmatogenous retinal detachments. Early surgery on one patient resulted in successful reattachment and 20/50 vision at a three-year follow-up visit. Other ocular findings included cataracts in two patients, dislocated lenses in one patient, and blepharoptosis in one patient.