A novel ROGDI gene mutation is associated with Kohlschutter-Tonz syndrome

Kohlschutter-tonz syndrome (KTS) is a rare neurodegenerative disorder that presents with seizures, developmental regression, characteristic hypoplastic dental enamel indicative of amelogenesis imperfecta and dysmorphologies. Genetic analysis has identified loss-of-function mutations within the coding region of the ROGDI gene in KTS patients of European or Jewish decent. In the present study, we have investigated the genetic status of ROGDI in a fourteen year old South Indian patient of Dravidian race born to consanguineous parents, who was clinically diagnosed with KTS STUDY DESIGN: To confirm the clinical diagnosis of KTS in the patient, primers were designed flanking each of the 11 exons of the ROGDI gene. We then used 50 nanograms of chromosomal DNA extracted from peripheral blood of the patient and his parents to amplify with above primers. The PCR amplicons were then subjected to direct sequencing with same set of primers.

Genetic analysis identified a novel homozygous nonsense mutation in exon 6 of the ROGDI gene; the mutation caused premature termination of ROGDI translation, resulting in truncation and loss of function of the ROGDI protein.

Taken together, the clinical presentation and loss-of-function mutation in the ROGDI gene confirms the clinical diagnosis of KTS.