Diagnosis Andersen–Tawil syndrome

cardiac muscle

two types of andersen–tawil syndrome distinguished genetic causes.

type 1, accounts 60 percent of cases of disorder, caused mutations in kcnj2 gene.
the remaining 40 percent of cases designated type 2; cause of condition in these cases unknown.

the protein made kcnj2 gene forms channel transports potassium ions muscle cells. movement of potassium ions through these channels critical maintaining normal functions of skeletal muscles used movement , cardiac muscle. mutations in kcnj2 gene alter usual structure , function of potassium channels or prevent channels being inserted correctly cell membrane. many mutations prevent molecule called pip2 binding channels , regulating activity. these changes disrupt flow of potassium ions in skeletal , cardiac muscle, leading periodic paralysis , irregular heart rhythm characteristic of andersen–tawil syndrome.researchers have not yet determined role of kcnj2 gene in bone development, , not known how mutations in gene lead developmental abnormalities found in andersen–tawil syndrome.