CD79A and hyperinsulinemic hypoglycemia, familial, 4: An additional case study showed a patient affected from SIgAD since childhood who - similarly to the vast majority of Selective IgA Deficiency - was asymptomatic until a Guillain Barrè syndrome was diagnosed at the time of COVID-19, when she developed anti-ganglioside antibodies (Pfeuffer et al., 2020).