POC1A and microcephaly: Aggregate analysis of the six known cases with biallelic POC1A variants and insulin resistance showed decreased birth weight and length mean (s.d.): −2.8 (0.9) and −3.7 (0.9) SDS, respectively), severe short stature mean (s.d.) height: −4.9 (1.7) SDS) and moderate microcephaly (mean occipitofrontal circumference −3.0 (range: −4.7 to −1.2)).