case_images: PMC10657692_01
case_images: -A: Pedigree showing segregation of the variant with the phenotype (ERM and/or muscle cramps). Individual II-3 complained of a history of mild muscle cramps, possibly a phenocopy. B: Bar chart showing CPK levels that decreased remarkably after initiating dantrolene therapy. Dantrolene was started at half of the effective dose at night to evaluate potential side effects including dizziness and fatigue. The patient tolerated it well, and the dose and time of administration were adjusted, to maintain the lowest effective dose, which was 0,5 mg/kg/day (= 10 mg of dantrolene), taken during the morning, which was the time when the patient was more active, and achieved a greater decrease in the level of CPK.
case_images: jnd-10-jnd230007-g001.jpg
case_images: PMC10657692_01_jnd-10-jnd230007-g001.jpg
case_images: jnd-10-jnd230007-g001
case_images: Family history (Fig. 1A) revealed a pattern of muscle cramps among some maternal relatives. As an attempt to control muscle symptoms, low-dose oral dantrolene was initiated according to the scheme detailed in Fig. 1B. AST level decreased from 117.5 U/L pre-dantrolene to 63.3 U/L post-dantrolene, while the mean ALT level decreased from 40.0 U/L pre-dantrolene to 25.3 U/L post-dantrolene. As expected, the administration of dantrolene in the morning, when the child was more physically active, demonstrated improved control over myalgia attacks and resulted in lower CPK levels (Fig. 1B).