Congenital Myopathy 22b, Severe Fetal, also known as cmyp22b, is related to congenital myopathy 22a, classic and myopathy. An important gene associated with Congenital Myopathy 22b, Severe Fetal is SCN4A (Sodium Voltage-Gated Channel Alpha Subunit 4). Affiliated tissues include bone and eye, and related phenotypes are polyhydramnios and decreased fetal movement