The oligophrenin-1 (OPHN1) gene is localized in the Xq12 region and it encodes the rho-GTPase-activating protein which spans 500 kb in size and consists of 25 exons. Gene plays crucial role in synaptic function and dendritic morphogenesis.
Here we report a 391 kb deletion in OPHN1 gene in a mother and her newborn male child with recognizable pattern of clinical and neuroradiological hallmarks. Mother has short stature, and her son has distinctive facial appearance, bilateral choroid plexus cysts and low birth weight (1600 g).
After clinical evaluation, the current large intragenic gene deletion was identified by microarray-CGH and confirmed by MLPA techniques. The P106 MRX probemix kit (MRC Holland C1- 0416, Amsterdam) and Coffalyser software were used for MLPA and Agilent sure print G3 HUMAN CGH 60k Microarray platform and Agilent cytogenomics 18.104.22.168 software (Singapore) were used for advance chromosomal genotyping for mother and his son in the presented results.
Presented results showed that mother with X chromosome deletion has a great risk to have a son with mental retardation due to deleted X chromosome transmission in 50% possibility. If the son has clinical findings, the genotype should be screened by using the advanced genetic methodology. Results also showed that once these cases are first diagnosed correctly, they may be candidate to IVF for preimplantation genetic diagnosis by giving appropriate genetic counseling. It is also comment that pregnant women who have the history of having X-linked mental retarded child or a mentally retarded brother need to be tested genetically for prenatal diagnosis.