About MRT66
Description
As described in its OMIM page, MRT66 is a non-syndromic1 autosomal2 recessive3 intellectual developmental disorder with delayed speech development, neuropsychiatric symptoms, and relatively normal life span. It associates with the gene C12orf44.
Based on our own experience, it also comes with hypotonia and autism spectrum disorder, both of which have also been reported in some of the research studies.
Cases
It is a recently discovered disorder and a very rare one. These are the individuals with MRT66, based on relevant research papers:
- a Saudi Arabian 12-year-old boy and his 8-year-old sister, reported by Alazami et al in 2015;
- two Finnish families, reported by Philips et al in 2017;
- a Dutch family, reported by the same.
- two Turkish siblings, reported by Reuter et al in 2017;
- two adult Armenian brothers, reported by Hancarova et al in 2019;
- two patients from an Iranian family, reported by Rashvand et al in 2022.
Hence, 7 families in total have been reported globally. The families in all cases are consanguineous5, except the two Finnish families, who were found to have common ancestors in the mid to late 18th century, and the Iranian family, which is not specified in the paper's abstract.
Then, there is our family, as well. Not reported in any research paper, which makes us think: how many more can there be?
Notes
Non-syndromic: MRT66 is not part of a syndrome. (Not sure what this means, though.)↩
Autosomal: it refers to the 22 numbered chromosomes as opposed to the sex chromosomes (X and Y).↩
Recessive: it passes from both parents onto their child—as opposed to dominant, which passes from only one parent↩
Chromosome 12 Open Reading Frame 4.↩
Consanguineous are the families of which the parents are biologically related—usually 1st or 2nd cousins. In many countries, this is so common a practice that 1:2 marriages are consanguineous.↩