We present a further family with YHFS and include a description of the oldest patient described to date, a 22‐year‐old Danish girl with two novel compound heterozygous mutations in TELO2. We highlight her clinical features, which include severe growth retardation and microcephaly of prenatal onset and marked global developmental delay; thus, a more severe presentation than seen in the original TELO2 mutation‐positive patients. This evidence concerns the gene TELO2 and microcephaly.