Volume 358, Issue 9284, Pages 801-807 (September 2001) Human epilepsy associated with dysfunction of the brain P/Q-type calcium channel  Anne Jouvenceau, PhD, Louise H Eunson, BSc, Alexander Spauschus, MD, Venkataswaran Ramesh, FRCP, Sameer M Zuberi, MRCP, Prof Dimitri M Kullmann, FRCP, Michael G Hanna, MD  The Lancet  Volume 358, Issue 9284, Pages 801-807 (September 2001) DOI: 10.1016/S0140-6736(01)05971-2 Copyright © 2001 Elsevier Ltd Terms and Conditions

Figure 1 New and previously identified mutations in α1A A: position of new mutation in α1A channel subunit. Four homologous domains, each consisting of six α helices, are indicated by roman numerals. Blue stars=previously described mutations, occurring in families with EA2. Green stars=new mutation described here, which occurs at the IVS6-C terminus junction. B: electropherogram of CACNA1A gene DNA sequence from the patient. The Lancet 2001 358, 801-807DOI: (10.1016/S0140-6736(01)05971-2) Copyright © 2001 Elsevier Ltd Terms and Conditions

Figure 2 R1820stop mutant α1A is non-functional but exerts a dominant negative effect on wild type allele A: selected traces from currents recorded from oocytes injected with wild-type (wt), mutant (R1820stop), and both wt and mutant α1A cDNA (Co-inj), evoked by 400 ms step depolarisation to +5 mV from a holding potential of −90 mV. Uninjected oocytes (UI) or oocytes expressed with auxiliary subunits only (β4α2δ) were used as a control. B–G: amplitude histograms of whole cell currents (evoked at voltages giving maximal currents). In each panel the current amplitude was normalised to wt (left bar). B: currents recorded in cells injected with wt were compared with cells injected with mutant R1820stop and with cells co-injected with wt: mutant (ratio 1:1), together with the auxiliary subunits β4 and α2δ. Inset: percentage of oocytes giving no detectable current in each case (defined as <120% of uninjected controls). Uninjected oocytes and oocytes injected with auxiliary subunits alone (β4α2δ) gave no current. C: the current amplitudes and dominant negative effect were unaltered when the amount of cDNA coding for β4 and α2δ were increased (as indicated by the ratios). D–G: The dominant negative effect persisted when δ3 was substituted for β4 (D), the β subunit was omitted (E), α2δ was omitted (F) or both β and α2δ were omitted (G). H: Sample K+ current traces recorded from oocytes injected with Kv1.1 alone, Kv1.1 and wt α1A, or Kv1.1 and mutant α1A cDNA. Step depolarisations (400 ms) to +40 mV were applied from a holding potential of -100 mV. I: K+ currents recorded in cells injected with Kv1.1 alone or with wt or mutant α1A subunits. Error bars indicate SE. *p<0·01, †p<0·001. ‡p<0·0001 compared with wt. For each histogram, the dashed line corresponds to 120% of the current obtained from uninjected oocytes. The Lancet 2001 358, 801-807DOI: (10.1016/S0140-6736(01)05971-2) Copyright © 2001 Elsevier Ltd Terms and Conditions

Figure 3 Comparison of wild-type (wt) and wt:R1820stop currents with respect to voltage and time-dependent kinetics A: voltage dependence of peak conductance of wt α1A alone and wt and mutant α1A cDNA co-expressed. Conductance is defined as Ipeak/(V-Erev), with Erev taken as +70 mV. B: mean activation time constant calculated from the rate of activation. C: graph of normalised conductance for currents obtained with wt α1A alone and wild-type-mutant co-expression, plotted against membrane potential. D: mean deactivation time constant plotted against a range of repolarisation potentials (Vtail) for recordings obtained with wt cDNA expressed alone or wt–mutant co-expression. Error bars indicate SE. The Lancet 2001 358, 801-807DOI: (10.1016/S0140-6736(01)05971-2) Copyright © 2001 Elsevier Ltd Terms and Conditions