Genetic and other etiologic-based testing during the NICU hospitalization, none of which revealed an explanation, included: karyotype (done prenatally due to concern for IUGR), high-density oligonucleotide/SNP microarray, biochemical testing for Smith–Lemli–Opitz syndrome through 7-dehydroxycholesterol level, a TORCH panel, and Russell–Silver syndrome testing (including H19 methylation and uniparental disomy for chromosome 7). Here, H19 is linked to fetal growth restriction.