SMN1 and proximal spinal muscular atrophy: MLPA was performed on all infants with undetectable SMN1 cycle threshold (Ct) levels to assess the copy numbers of exons 7 and 8 in both SMN1 and SMN2. We identified one patient with SCID, two patients with XLA, and nine patients with SMA, one of whom also had Wiskott–Aldrich Syndrome (WAS).