SERF1A and proximal spinal muscular atrophy: In some severe cases of SMA, loss of the NAIP (neuronal apoptosis protein inhibitor), GTF2H2A (general transcription factor IIH, p44), and SERF1A (small EDRK-rich factor 1A, H4F5A) genes are also observed [28,29,30,31,32,33].