Mucolipidosis Type IV in Omani Families with a Novel MCOLN1 Mutation: Search for Evidence of Founder Effect: Search for Evidence of Founder Effect

Mucolipidosis Type IV (MLIV) is caused by a deficiency of the mucolipin cation channel
encoded by Mucolipin TRP Cation Channel 1 gene (MCOLN1). It is a slowly progressive neurodevelopmental
and neurodegenerative disorder causing severe psychomotor developmental delay
and progressive visual impairment, which is often misdiagnosed as cerebral palsy. We describe six
patients with MLIV from two Omani families with a novel c.237+5G>A mutation in the MCOLN1
gene predicted to affect mRNA splicing. Mutation screening with a high-resolution melting (HRM)
assay in a large population sample did not detect this mutation in control subjects. This report
highlights the importance of considering MLIV in the differential diagnosis of patients in a pediatric
age group with cerebral palsy-like presentation. Although the same rare mutation was seen in two
apparently unrelated families, this was not seen in the sample screened from the general population.
The HRM assay provides a cost-effective assay for population screening for the c.237+5G>A mutation.