Mouse Genome Informatics
involves: 129
phenotype observed in females
phenotype observed in males
N normal phenotype

Vacuolar myopathy in Cacna1stm1.1Cann/Cacna1stm1.1Cann muscle and rare dilated cisternae in Cacna1stm1.1Cann/Cacna1s+ sarcoplasmic reticulum

• massive dilation of the transverse tubules and cisternae of the sarcoplasmic reticulum
• in the gastrocnemius at 4 months and the tibialis anterior at 9 months
• calcium transients elicited by filed stimulation of dissociated flexor digitorum brevis fibers are reduced compared to in wild-type mice
• mice exhibit in vivo hypokalemic periodic paralysis from glucose plus insulin challenge with reduced relative CAMP and force compared with wild-type mice
• fibers exhibit reduced excitability caused by depolarization of the resting potential compared with wild-type fibers
• flexor digitorum brevis fibers exhibit loss of function changes for ionic current conduction compared with wild-type fibers
• the amplitude of calcium ion transient under voltage clamp conditions is 3-fold smaller than in wild-type fibers
• reduced extensor digitorum longus muscle peak force in male and female mice
• following low potassium challenge, extensor digitorum longus muscles in mice exhibit reduced peak force and a rapid decline in force with incomplete recovery after return to higher potassium levels compared with wild-type mice
• however, mice do not have myotonia
• vacuolar myopathy with scattered central nuclei in the gastrocnemius at 4 months and the tibialis anterior at 9 months

Mouse Models of Human Disease
Hypokalemic Periodic Paralysis, Type 1; HOKPP1 170400 J:19367