Further delineation of achondroplasia-hypochondroplasia complex with long-term survival.

Achondroplasia-hypochondroplasia (ACH-HCH) complex is caused by the presence of two different pathogenic variants in each allele of FGFR3 gene. Only four patients with confirmed molecular diagnoses have been reported to date, and the phenotype has not been fully defined. Here, we describe a Mexican patient with a confirmed molecular diagnosis of ACH-HCH complex. This patient exhibits intellectual disability, has a history of seizures, experienced multiple cardiorespiratory complications during early childhood, and required foramen magnum decompression. However, he now shows a stable health condition with long-term survival (current age, 18 years). This case is particularly relevant to our understanding of ACH-HCH complex and for the genetic counseling of couples who are affected with ACH or HCH.