Side effects on the central nervous system and the heart may be severe and potentially fatal. However, toxicity usually occurs only at plasma levels which are rarely reached if proper anesthetic techniques are adhered to. High plasma levels might arise, for example, when doses intended for epidural or intrasupport tissue administration are accidentally delivered as intravascular injection. Emotional reactions
When patients are emotionally affected in the form of nervousness or fear, it can lead to vasovagal collapse. This is the anticipation of pain during administration that activates the parasympathetic nervous system while inhibiting the orthosympathetic nervous system. What results is a dilation of arteries in muscles which can lead to a reduction in circulating blood volume inducing a temporary shortness of blood flow to the brain. Notable symptoms include restlessness, visibly looking pale, perspiration and possible loss of consciousness. In severe cases, clonic cramps resembling an epileptic insult may occur.On the other hand, fear of administration can also result in accelerated, shallow breathing, or hyperventilation. The patient may feel a tingling sensation in hands and feet or a sense of light-headedness and increased chest pressure.Hence, it is crucial for the medical professional administrating the local anaesthesia, especially in the form of an injection, to ensure that the patient is in a comfortable setting and has any potential fears alleviated in order to avoid these possible complications. Central nervous system
Depending on local tissue concentrations of local anesthetics, excitatory or depressant effects on the central nervous system may occur.
Prevalence
According to three OMIM pages for this condition, about 78 families across the world are known to have this condition, this includes both familial and sporadic cases with confirmed genetic basis (thus, potential to spread to offspring and turn it into a familial case). Most (if not all) of these families are of East Asian (Japanese and Chinese in particular) descent. OMIM divided this condition into subtypes due to the different genetic causes and slightly different symptoms the three of them exhibit. The following list comprises the number of families described in medical literature each of these subtypes has:

# 164310OCULOPHARYNGODISTAL MYOPATHY 1; OPDM1: 37 families
# 618940OCULOPHARYNGODISTAL MYOPATHY 2; OPDM2: 30 families
# 619473OCULOPHARYNGODISTAL MYOPATHY 3; OPDM3: 11 families. History
This condition was first discovered in 1977 by E Sayotoshi et al. when they described an unspecified amount of people from 4 families who suffered from an "autosomal dominant, heredofamilial myopathy" which consisted in "slowly progressive ptosis and extraocular palsy, and weakness of the masseter, facial, and bulbar muscles, as well as distal involvement of the limbs starting around 40 years of age or later. "In 2019, Hiroyuki Ishiura et al. discovered a heterozygous trinucleotide repeat expansion in the 5-prime untranslated region of the LRP12 gene in 5 patients with the condition, the trinucleotide sequence consisted of one C (cytosine) and two Gs (guanine).