Short Stature and Good Efficacy of GH Therapy in the Youngest Child with a Novel Splice Variant in ACAN

We report the youngest case with short stature caused by a novel heterozygous splicing ACAN variant. A boy aged 4 months and 10 days presented to the clinic with the main complaint of short stature. Achondroplasia was suspected prenatally due to the relatively short fetal femur and large double parietal diameter. However, amniocentesis and hotspot mutation (c.1138G>A) of the FGFR3 gene had been excluded. The child had short stature with macrocephaly, short neck, and mildly flat nasal bridge. On performing whole exon sequencing, a novel heterozygous splice mutation (c. 2266+1G>A) was identified in the ACAN gene, which has not been reported before. The variant was confirmed by Sanger sequencing in the family, showing no mutations in the parents.