Clinical characteristics of pseudoachondroplasia and analysis of COMP gene mutation / 中华内分泌代谢杂志

Objective This article reported the clinical characteristics and gene mutations of two pseudoachondroplasia cases, and made a literature review in order to improve clinicians' understanding of the disease. Methods Clinical features of two patients who were short stature accompanied with skeletal deformities were summarized, and they accepted whole exome sequencing. We also reviewed literature to summarize the clinical characteristics and known gene research progress of all reported Chinese pseudoachondroplasia cases. Results The two patients' clinical characteristics were short limbdwarfism with skeletal deformity. Genetic results showed that there were two heterozygous mutations in the cartilage oligomeric matrix protein (COMP) gene of the two patients, c.14171419delGAC and c.1552G>A, respectively. Up to March 2019, a total of 58 cases of pseudoachondroplasia have been reported in China. The median height of these patients is-5.03 SDS. The clinical features include abnormal gait, short limbs, short fingers/toes, scoliosis, bracelet sign, ankle sign and other skeletal deformities. COMP is the pathogenic gene and mutations mainly located in calmodulin-like domains. The hotspot mutation is c. 14171419delGAC. Conclusions Pseudoachondroplasia is a kind of rare genetic disease characterized by short stature and skeletal deformities. The clinical and genetic characteristics of the disease were summarized, which may improve the early diagnosis rate.

Clinical features and gene mutation analysis of COMP in eight patients with pseudoachondroplasia / 中华内分泌代谢杂志

The clinical features and the mutation of cartilage oligomer matrix protein (COMP) gene were analyzed in 8 patients with pseudoachondroplasia (PSACH).The clinical data and the peripheral blood from 5 male and 3 female probands,their pedigree members,and 250 unrelated volunteers were collected.Eight patients who were sporadic cases,had been detected mutation of COMP gene by DNA sequencing.PSACH is a skeletal disorder characterized by short stature,joint laxity,and early-onset osteoarthritis.The heights of 8 patients were significantly lower than the average level by 3 standard deviations,with short limbs and deformities of legs.Radiographs showed flattening of vertebrae with anterior beaking or tonguing in children and osteoarthritis in adults.As to the patients with short limb dwarfism,short toes,and abnormal radiography findings,PSACH should be suspected and could be confirmed by detection of COMP gene mutation.

Clinical characteristics of pseudoachondroplasia and analysis of COMP gene mutation / 中华内分泌代谢杂志

Objective@#This article reported the clinical characteristics and gene mutations of two pseudoachondroplasia cases, and made a literature review in order to improve clinicians′ understanding of the disease.@*Methods@#Clinical features of two patients who were short stature accompanied with skeletal deformities were summarized, and they accepted whole exome sequencing. We also reviewed literature to summarize the clinical characteristics and known gene research progress of all reported Chinese pseudoachondroplasia cases.@*Results@#The two patients′ clinical characteristics were short limbdwarfism with skeletal deformity. Genetic results showed that there were two heterozygous mutations in the cartilage oligomeric matrix protein (COMP) gene of the two patients, c. 1417_1419delGAC and c. 1552G>A, respectively. Up to March 2019, a total of 58 cases of pseudoachondroplasia have been reported in China. The median height of these patients is -5.03 SDS. The clinical features include abnormal gait, short limbs, short fingers/toes, scoliosis, bracelet sign, ankle sign and other skeletal deformities. COMP is the pathogenic gene and mutations mainly located in calmodulin-like domains. The hotspot mutation is c. 1417_1419delGAC.@*Conclusions@#Pseudoachondroplasia is a kind of rare genetic disease characterized by short stature and skeletal deformities. The clinical and genetic characteristics of the disease were summarized, which may improve the early diagnosis rate.

Clinical features and gene mutation analysis of cartilage oligomeric matrix protein in a family with pseudoachondroplasia / 中华内分泌代谢杂志

Objective To investigate cartilage oligomeric matrix protein( COMP) gene mutation in a three-generation pedigree with two cases of pseudoachondroplasia, and to definitize genotype-phenotype correlation. Methods The clinical data and peripheral blood were collected from the patients with pseudoachondroplasia and their family members. All the 19 exons and their flanking sequences of COMP gene in two patients and three unaffected family numbers and 50 unrelated individuals were analyzed by PCR amplification and direct sequencing. Results The proband, a 6-year-old girl presented with typical clinical features of pseudoachondroplasia, including disproportionate short limb dwarfism, staggering gait, double genu varus deformity, and wider clinical and imaging long bone metaphysis. The 33-year-old father showed a similar manifestation including disproportionate short limb dwarfism and double genu varus deformity, and was performed correcting operation on lower limbs for double genu varus at the age of 10 years. DNA sequencing analysis of the COMP gene revealed a del mutation ( c. 1417 1419delGAC)in exon 13 in two patients with pseudoachondroplasia, but not in the other unaffected members from the pedrgree and 50 control subjects. Conclusion A del mutation c. 1417 1419delGAC of COMP gene may contribute to the disease in the pedigree.

Progress in the diagnosis and treatment of short-limb inherited short stature patients with skeletal dysplasia / 国际儿科学杂志

Achondroplasia,hypochondroplasia and pseudoachondroplasia are all inherited skeletal system diseases resulting in short stature with short limbs.The clinical characteristics of the three diseases are similar and easily confused.In recent years,the genetic researches of the three diseases have made great progress,providing the basis for the diagnosis and differential diagnosis of the disease.In addition,the application of recombinant human growth hormone treatment in the three diseases also has taken the preliminary results.This article reviews the clinical features,identification,genetic analysis and growth hormone therapy of three disases.

Altered Synthesis of Cartilage-Specific Proteoglycans by Mutant Human Cartilage Oligomeric Matrix Protein

BACKGROUND: The mechanism by which mutant cartilage oligomeric matrix protein (COMP) induces a pseudoachondroplasia phenotype remains unknown, and the reason why a mutation of a minor protein of the growth plate cartilage causes total disruption of endochondral bone formation has not yet been determined. The current study was performed to investigate the effects of mutated COMP on the synthesis of the cartilage-specific major matrix proteins of Swarm rat chondrosarcoma chondrocytes. METHODS: The Swarm rat chondrosarcoma chondrocytes transfected with a chimeric construct, which consisted of a mutant gene of human COMP and an amino acid FLAG tag sequence, were cultured in agarose gel. Formation of extracellular proteoglycan and type-II collagen by the cells was evaluated by immunohistochemical staining and measuring the (35)S-sulfate incorporation. RESULTS: No difference was observed for the detection of type-II collagen among the cell lines expressing mutant COMP and the control cell lines. Histochemical staining of sulfated proteoglycans with safranin-O showed that lesser amounts of proteoglycans were incorporated into the extracellular matrix of the chondrocytes transfected with the mutant gene. (35)S-sulfate incorporation into the cell/matrix fractions demonstrated markedly lower radiolabel incorporation, as compared to that of the control cells. CONCLUSIONS: Mutation of COMP has an important impact on the processing of proteoglycans, rather than type-II collagen, in the three-dimensional culture of Swarm rat chondrosarcoma chondrocytes.

A Novel COMP Gene Mutation in a Korean Kindred with Multiple Epiphyseal Dysplasia

Multiple epiphyseal dysplasia (MED) is a clinically and genetically heterogeneous chondroplasia, characterized by delayed development of the ossification centers and, deformities of the extremities that involve only the epiphysis and result in mild short stature. Mutations in the cartilage oligomeric matrix protein (COMP) gene are most commonly found, and most of the mutations are located in the calmodulin-like repeats and the C-terminal domain. We report a Korean kindred of?12 family members with MED in four generations who were found to have a novel mutation in the COMP gene. A pedigree showed early onset osteoarthritis requiring arthroplasty that was an autosomal dominant inherited trait. Radiological examinations demonstrated the presence of osteochondral defects in the medial femoral condyles, and the knee and hip joints showed variable degrees of precocious degenerative changes. Mutation analysis of the COMP gene in the proband and five other affected family members identified a novel missense mutation, c.1280G>C (p.Gly427Ala) in exon 12, which was not found in three unaffected family members. Direct sequencing of the COMP gene may yield pathogenic mutations in dominantly inherited MED cases, and may provide opportunities of carrier detection among high-risk family members, leading to genetic counseling for early diagnosis and intervention before the onset of complications.