AP4E1 and autosomal recessive spinocerebellar ataxia 18: Moreno-De-Luca et al. (2011) used a custom-designed oligonucleotide array in discovering AP4E1, the gene responsible for SPG51 (OMIM# 613744). Moreno-De-Luca et al. (2011) used a genome-wide microarray in their study to identify a region of interest, and then further analyzed the identified region with a higher-resolution microarray. In another study, Utine et al. (2013) used an SNP array in discovering the gene causing SCAR18 (OMIM # 616204). Guided by array-based homozygosity mapping, Utine et al. (2013) identified deletions in the third and fourth exons of GRID2 in three Turkish siblings.