OBJECTIVES: To study the clinical features and fibroblast growth factor receptor 3 (FGFR3) gene mutations of children with achondroplasia (ACH) through an analysis of 17 cases. METHODS: A retrospective analysis was performed on the clinical data and FGFR3 gene detection results of 17 children with ACH who were diagnosed from January 2009 to October 2021. RESULTS: Of the 17 children with ACH, common clinical manifestations included disproportionate short stature (100%, 17/17), macrocephaly (100%, 17/17), trident hand (82%, 14/17), and genu varum (88%, 15/17). The common imaging findings were rhizomelic shortening of the long bones (100%, 17/17) and narrowing of the lumbar intervertebral space (88%, 15/17). Major complications included skeletal dysplasia (100%, 17/17), middle ear dysfunction (82%, 14/17), motor/language developmental delay (88%, 15/17), chronic pain (59%, 10/17), sleep apnea (53%, 9/17), obesity (41%, 7/17), foramen magnum stenosis (35%, 6/17), and hydrocephalus (24%, 4/17). All 17 children (100%) had FGFR3 mutations, among whom 13 had c.1138G>A hotspot mutations of the FGFR3 gene, 2 had c.1138G>C mutations of the FGFR3 gene, and 2 had unreported mutations, with c.1252C>T mutations of the FGFR3 gene in one child and c.445+2_445+5delTAGG mutations of the FGFR3 gene in the other child. CONCLUSIONS This study identifies the unreported mutation sites of the FGFR3 gene, which extends the gene mutation spectrum of ACH. ACH is a progressive disease requiring lifelong management through multidisciplinary collaboration.
Achondroplasia/genetics* ; Child ; Humans ; Mutation ; Osteochondrodysplasias/genetics* ; Receptor, Fibroblast Growth Factor, Type 3/genetics* ; Retrospective Studies

OBJECTIVETo investigate the clinical symptoms and potential mutation in FGFR3 gene for a family featuring hereditary dwarfism in order to attain diagnosis and provide prenatal diagnosis.

METHODSFive patients and two unaffected relatives from the family, in addition with 100 healthy controls, were recruited. Genome DNA was extracted. Exons 10 and 13 of the FGFR3 gene were amplified using polymerase chain reaction (PCR). PCR products were sequenced in both directions.

RESULTSAll patients had similar features including short stature, short limbs, lumbar hyperlordosis but normal craniofacial features. A heterozygous mutation G1620T (N540K) was identified in the cDNA from all patients but not in the unaffected relatives and 100 control subjects. A heterozygous G380R mutation was excluded.

CONCLUSIONThe hereditary dwarfism featured by this family has been caused by hypochondroplasia (HCH) due to a N540K mutation in the FGFR3 gene.

Base Sequence ; DNA Mutational Analysis ; Dwarfism ; genetics ; Exons ; Female ; Heterozygote ; Humans ; Male ; Mutation ; Receptor, Fibroblast Growth Factor, Type 3 ; genetics

OBJECTIVE[corrected] To investigate the mutation at the transmembrane domain of fibroblast growth factor receptor 3 (FGFR3) nucleotide 1138 site for identifying the major pathologic mechanism of achondroplasia (ACH) and to evaluate the efficacy of denaturing gradient gel electrophoresis(DGGE) method for screening the point mutations.

METHODSThe genomic DNA from 17 clinically diagnosed ACH patients where analysed by polymerase chain reaction-restriction fragment length polymorphism(PCR-RFLP) with Sfc I and Msp I restriction endonucleases and by PCR-DGGE technique for screening.

RESULTSG to A transition mutation at nucleotide 1138 was detected in 14/17 of the ACH patients as heterozygotes by PCR-RFLP with Sfc I digestion. No 1138 G to C transition was detected by Msp I digestion. All of the 14 samples with G to A mutation were also found to be positive for point mutation by PCR-DGGE. No mutation was detected in 3 negative samples by PCR-RFLP, implying that there was actually no point mutation in this amplified region.

CONCLUSIONNucleotide 1138 in transmembrane domain of FGFR3 gene is the hot point for mutation in ACH and hence its major pathologic cause. PCR-DGGE is a sensitive and reliable technique for point mutation screening, especially for the heterozygotes.

Achondroplasia ; genetics ; DNA ; chemistry ; genetics ; DNA Mutational Analysis ; Female ; Humans ; Male ; Point Mutation ; Polymorphism, Restriction Fragment Length ; Polymorphism, Single-Stranded Conformational ; Protein-Tyrosine Kinases ; Receptor, Fibroblast Growth Factor, Type 3 ; Receptors, Fibroblast Growth Factor ; genetics

OBJECTIVETo establish the mouse model of Gly374Arg mutation in fibroblast growth factor receptor 3(Fgfr3) and to analyze the phenotype of the mutant mice.

METHODSThe double PCR was used to introduce Gly374Arg point mutation into mouse Fgfr3. The electroporation of embryonic stem(ES) cells was carried out with targeting vector. The targeted ES cells were screened by Positive-Negative Selection of G418 and Ganciclovir, and Southern blot. The correct targeted ES cells were microinjected into blastula. Finally, mutant mice were obtained by crossing between EIIa-Cre transgenic mice and mice carrying recombined mutant Fgfr3 allele. The mice were genotyped by PCR, and phenotype was observed by skeleton staining, histology, etc.

RESULTSFgfr3-Gly374Arg mutant mice exhibited small size, short tail, macrocephaly and had dome-shaped heads, the epiphyseal growth plates of mutant mice were narrower, and the hypertrophic chondrocyte zone was also obviously decreased. Meanwhile, the majority of female mice were infertile, and the uterus, ovary and mammal gland in mutant female mice were also smaller and underdeveloped.

CONCLUSIONThe model of Fgfr3-Gly374Arg mutation causing achondroplasia in mice has been established successfully.

Achondroplasia ; genetics ; pathology ; Amino Acid Substitution ; Animals ; Disease Models, Animal ; Female ; Humans ; Male ; Mice ; Ovary ; pathology ; Point Mutation ; Protein-Tyrosine Kinases ; genetics ; Receptor, Fibroblast Growth Factor, Type 3 ; Receptors, Fibroblast Growth Factor ; genetics ; Uterus ; pathology

OBJECTIVETo clarify the patients' pathogenic mechanism in an achondroplasia family not according with the genetic law of autosomal dominant inheritance disease at gene level.

METHODSGenomic DNA from peripheral blood of all members in this family was used for amplification of the exon 10 of fibroblast growth factor receptor 3(FGFR3) gene by PCR; mutation was detected by DNA sequencing and identified by restriction endonuclease MaeIII.

RESULTSA new mutation of A to T at nucleotide 1180 was found in patients but not in unaffected members.

CONCLUSIONCombined with pedigree analysis, it was summarized that achondroplasia patients in this family might result from this new mutation.

Achondroplasia ; genetics ; pathology ; Base Sequence ; DNA ; chemistry ; genetics ; DNA Mutational Analysis ; Family Health ; Female ; Humans ; Male ; Middle Aged ; Mutation ; Pedigree ; Protein-Tyrosine Kinases ; Receptor, Fibroblast Growth Factor, Type 3 ; Receptors, Fibroblast Growth Factor ; genetics

Achondroplasia ; genetics ; Adult ; Amino Acid Sequence ; Genes, Dominant ; Humans ; Male ; Molecular Sequence Data ; Mutation ; Polymorphism, Restriction Fragment Length ; Receptor, Fibroblast Growth Factor, Type 3 ; chemistry ; genetics ; physiology

OBJECTIVETo research on the reliability of diagnosing achondroplasia (ACH) on single cell level and to provide a basis for preimplantation genetic diagnosis(PGD).

METHODSThe high-frequency mutation region G380R of fibroblast growth factor receptor 3(FGFR3) gene was amplified by nested-PCR with single lymphocyte and single blastomere. The products of PCR were digested by restriction enzyme Bfm I, then the digested products were detected by 10% polyacrylamida gel electrophoresis(PAGE).

RESULTSThe amplification success rate, allele dropout rate and correct diagnosis rate of single lymphocyte's PCR were 90.4%, 8.2% and 91.8%,respectively. The amplification success rate of single blastomere was 75.4%.

CONCLUSIONThe diagnosis of ACH by single cell nested-PCR is comparatively stable and reliable.

Achondroplasia ; diagnosis ; genetics ; DNA Mutational Analysis ; Humans ; Molecular Diagnostic Techniques ; methods ; Mutation ; Polymerase Chain Reaction ; methods ; Preimplantation Diagnosis ; Receptor, Fibroblast Growth Factor, Type 3 ; genetics ; Sensitivity and Specificity

OBJECTIVETo diagnose achondroplasia prenatally by FGFR3 gene detection.

METHODSSeventy-eight fetuses affected by short-limb dysplasias were recruited. Umbilical blood sampling was employed to obtain fetal blood for karyotyping and FGFR3 gene detection. Genomic DNA was extracted, and the exon 10 of the FGFR3 gene was amplified. PCR amplicons were analyzed by DNA sequencing and restriction fragment length polymorphism with Bfm I. The FGFR3 exon 10 from the parents of the positive fetuses was screened by the same method.

RESULTSIn 78 fetuses affected with short-limb dysplasias, 8 cases had G1138A heterozygotic mutation and normal karyotype, and were diagnosed as achondroplasia. The other 70 fetuses had normal nucleotide at nucleotide 1138 in exon 10 of FGFR3, therefore were excluded from achondroplasia. Only one father in parents of the 8 achondroplasia fetuses also had the G1138A mutation.

CONCLUSIONAchondroplasia could be diagnosed prenatally in the fetuses affected with short-limb dysplasias by using PCR-RFLP and DNA sequencing of the exon 10 of the FGFR3 gene.

Achondroplasia ; diagnosis ; genetics ; DNA Mutational Analysis ; Female ; Humans ; Male ; Polymorphism, Restriction Fragment Length ; Pregnancy ; Prenatal Diagnosis ; methods ; Receptor, Fibroblast Growth Factor, Type 3 ; genetics

OBJECTIVETo identify the causative mutations in five individuals affected with dyschondroplasia and develop an efficient procedure for detecting hot spot mutations of the FGFR3 gene.

METHODSGenomic DNA was extracted from peripheral blood samples with a standard phenol/chloroform method. PCR-Sanger sequencing was used to analyze the causative mutations in the five probands. PCR-high resolution melting (HRM) was developed to detect the identified mutations.

RESULTSA c.1138G>A mutation in exon 8 was found in 4 probands, while a c.1620C>G mutation was found in exon 11 of proband 5 whom had a mild phenotype. All patients were successfully distinguished from healthy controls with the PCR-HRM method. The results of HRM analysis were highly consistent with that of Sanger sequencing.

CONCLUSIONThe Gly380Arg and Asn540Lys are hot spot mutations of the FGFR3 gene among patients with ACH/HCH. PCR-HRM analysis is more efficient for detecting hot spot mutations of the FGFR3 gene.

DNA Mutational Analysis ; methods ; Female ; Humans ; Male ; Mutation ; genetics ; Polymerase Chain Reaction ; methods ; Receptor, Fibroblast Growth Factor, Type 3 ; genetics ; Transition Temperature

OBJECTIVE: To explore strategies of prenatal genetic testing for fetuses featuring abnormal skeletal development. METHODS: Clinical data of 17 fetuses with skeletal dysplasia was collected. The results of genetic testing and outcome of pregnancy were analyzed. RESULTS: For 12 fetuses, the femur-to-foot length ratio was less than 0.9. Thirteen fetuses had a positive finding by genetic testing. One fetus was diagnosed with chromosomal aneuploidy, three were diagnosed with microdeletion/microduplications, and nine were diagnosed with hereditary bone diseases due to pathological variants of FGFR3, COL1A2, GPX4 or ALPL genes. CONCLUSION For fetuses with skeletal dysplasia characterized by short femur, in addition to chromosomal karyotyping and microarray analysis, sequencing of FGFR3 and other bone disease-related genes can improve the diagnostic rate.
Bone Diseases, Developmental/genetics* ; Female ; Fetus/diagnostic imaging* ; Genetic Testing ; Humans ; Karyotyping ; Pregnancy ; Prenatal Diagnosis ; Receptor, Fibroblast Growth Factor, Type 3/genetics* ; Ultrasonography, Prenatal