mthfr gene

I have quite a few cousins and nephews who are mentally retarded.  Three of my mothers sisters have had mentally retarded children and some of their daughters have had mentally retarded children.  I also have a sister with a mentally retarted child.  All the retarded children are male.  We also have a family history of colon disease, stroke, scoliosis.  Three of my cousins tested positive for this gene.  Should the rest of our family be tested.  Is this a rare occurance???  

Thanks

[Jordanna Joaquina, MS, CGC]

We recommend that you meet with a genetic counselor regarding your family history of mental retardation and other conditions. There are genetic causes of mental retardation. The most common inherited cause of mental retardation called Fragile X syndrome occurs more frequently in males. A genetic counselor can take a detailed personal and family history in order to provide specific risk assessment for mental retardation, colon disease, stroke, scoliosis and MTHFR in the family. Specific MTHFR variations are relatively common in Caucasians of European ancestry. A family history of multiple generations of males with mental retardation is not common. A genetic counselor can discuss the benefits and limitations of your genetic testing options as well.

[magpie888]

A related discussion, MTHFR re: Chiari and Aspergers was started.