SLC52A3, A Brown-Vialetto-van Laere Syndrome Candidate Gene is Essential for Mouse Development but Dispensable for Motor Neuron Differentiation — SLC52A3, A Brown–Vialetto–van Laere syndrome candidate gene is essential for mouse development, but dispensable for motor neuron differentiation — SLC52A3, A Brown–Vialetto–van Laere syndrome candidate gene is essential for mouse development, but dispensable for motor neuron differentiation