According to Charcot-Marie-Tooth News, a Chinese family of five who all have the same type of Charcot-Marie-Tooth (CMT) disease share something else in common as well. Not only do they all have CMTX4, a certain type of CMT, but they also all share the same gene mutation. Specifically, this gene is called AIFM1.
To give some context, Charcot-Marie-Tooth disease is a fairly common, but still rare, inherited neurological disorder. There are many types of CMT, and each different type has a different mutated gene associated with it. That said, all types of CMT cause nerves to degenerate. Ultimately, this breaks down communication to the muscles and those who have CMT struggle with weakness and difficulty moving. There is no cure for CMT but various forms of therapy may help those who struggle with CMT cope with the symptoms. To read more about the disorder, click here.
In this particular study, scientists performed research on a Chinese family that carried a CMT diagnosis. Within the family, five were affected by the disease over five generations. The first of these five affected was 10-years-old when he experienced weakness in his lower limbs and some issues with balance.
By the time this first diagnosed family member was 25-years-old, muscle weakness had progressed and sensation was escaping his ankles. That said, the intellectual function of this patient was deemed normal at this time.
As for the other four family members with CMT diagnoses, their symptoms began with weakness in the legs and then atrophy. Two of these patients were very young when symptoms became evident—5 and 7-years-old. These same two patients also experienced much more rapid muscle degeneration.
Though age of onset and symptoms varied among the family members, a few things remained the same. All five of the family members diagnosed with CMT exhibited distal muscular atrophy below the knee along with steppage gait and pes cavus.
To study this family’s genetics further, genetic analyses were run on all of the family members, including those unaffected by CMT. The data showed that all the CMT patients in the family carried a hemizygous missense gene mutation while those who were not diagnosed with CMT did not have the same mutation.
These “hemizygous missesnse gene mutations” are basically the result of an error in copying genetic information. Instead of two copies of the gene, the nucleotide only produces one copy of it.
By figuring this out and analyzing the patients in the family, researchers decided that this mutation “was mainly involved in peripheral nerves [lesions] with relatively slight muscular changes.”
Most data is good data, and this is no exception. Scientists are pretty happy with the findings and the implications of them. “In conclusion, the identification of a novel missense AIFM1 mutation in a Chinese family in our study expands our knowledge of the genetic spectrum of AIFM1-associated diseases,” they said.
Not only this, but this research is helpful for scientists to learn even more about the specific type of CMT affecting this family (CMTX4). To read more about this research, click here.
