FGF9 and microcephaly: Some associated features could orient towards a specific underlying cause: microcephaly (ESCO2‐related disorders, microcephaly–micromelia syndrome), craniosynostosis (FGF‐related disorders), underossified skull and/or first digit aplasia or hypoplasia (CYP26B1‐biallelic variants), girdle deformities (Cousin syndrome), multiple synostosis without craniosynostosis (multiple synostosis syndrome related to NOG/GDF5/GDF6/FGF9 variant), genital variations (POR‐related Antley–Pixler syndrome), thrombocytopenia (TAR syndrome) and nail anomalies (WNT7A‐biallelic variants) (Table 2).