OBJECTIVES: To study genotype-phenotype correlations in children with FGFR3 variants and to improve clinical recognition of related disorders. METHODS: Clinical data of 95 patients aged 0-18 years harboring FGFR3 variants, confirmed by whole‑exome sequencing at Shanghai Children's Medical Center from January 2012 to December 2023, were retrospectively reviewed. Detailed phenotypic characterization was performed for 22 patients with achondroplasia (ACH) and 10 with hypochondroplasia (HCH). RESULTS: Among the 95 patients, 52 (55%) had ACH, 24 (25%) had HCH, 9 (9%) had thanatophoric dysplasia, 3 (3%) had syndromic skeletal dysplasia, 2 (2%) had severe achondroplasia with developmental delay and acanthosis nigricans, and 5 (5%) remained unclassified. A previously unreported FGFR3 variant, c.1663G>T, was identified. All 22 ACH patients presented with disproportionate short stature accompanied by limb dysplasia, commonly with macrocephaly, a depressed nasal bridge, bowed legs, and frontal bossing; complications were present in 17 (77%). The 10 HCH patients predominantly exhibited disproportionate short stature with limb dysplasia and depressed nasal bridge. CONCLUSIONS ACH is the most frequent phenotype associated with FGFR3 variants, and missense variants constitute the predominant variant type. The degree of FGFR3 activation appears to correlate with the clinical severity of skeletal dysplasia.
Humans ; Receptor, Fibroblast Growth Factor, Type 3/genetics* ; Child ; Male ; Child, Preschool ; Female ; Infant ; Adolescent ; Dwarfism/genetics* ; Achondroplasia/genetics* ; Lordosis/genetics* ; Infant, Newborn ; Retrospective Studies ; Genetic Association Studies ; Bone and Bones/abnormalities* ; Phenotype ; Limb Deformities, Congenital

OBJECTIVETo analyze the clinical manifestations, bone X-ray findings and genetic analysis results of three short-limb inherited short stature diseases: achondroplasia (ACH), hypochondroplasia (HCH) and pseudoachondroplasia (PSACH).

METHODSThe clinical manifestations, bone X-ray findings, and genetic analysis results of 10 children with genetically confirmed short-limb inherited short stature diseases, including 4 cases of ACH 3 cases of HCH, and 3 cases of PSACH, were analyzed.

RESULTSThe 10 patients had a mean body height of -3.69±1.79 SD, a mean sitting height/standing height ratio of 0.65±0.03, and a mean finger spacing/body height ratio of 0.93±0.04. Four ACH cases and 3 PSACH cases showed typical bone X-ray findings; one HCH case showed a smaller sciatic notch, and another HCH case showed no widening of interpedicular distance. G380R mutation in FGFR3 gene was detected in 3 of 4 ACH cases, and Y278C mutation in the other ACH case, N540K mutation in FGFR3 gene was detected in 3 HCH cases, and heterozygous mutations in COMP gene were detected in 3 PSACH cases.

CONCLUSIONSChildren with ACH and PSACH have severer short stature and skeletal deformities than children with HCH, who have mild, atypical clinical manifestations. Bone X-ray and genetic analysis are helpful for the diagnosis and differential diagnosis of the three diseases. The mutational hotspots in two genes are involved in the three diseases, which is conducive to clinical genetic diagnosis.

Achondroplasia ; diagnostic imaging ; genetics ; Bone and Bones ; abnormalities ; diagnostic imaging ; Child ; Child, Preschool ; Dwarfism ; diagnostic imaging ; genetics ; Female ; Humans ; Limb Deformities, Congenital ; diagnostic imaging ; genetics ; Lordosis ; diagnostic imaging ; genetics ; Male ; Mutation ; Radiography ; Receptor, Fibroblast Growth Factor, Type 3 ; genetics