Three cases of Schmid metaphyseal achondroplasia in one family

QI Rui-rui; LUO Yan-fei; YAO Qi; Mireguli·maimaiti

doi:10.3969/j.issn.2095-252X.2023.12.007

Abstract：Objective To retrospectively analyze the clinical data of a child with Schmid metaphyseal chondroplasia,who was admitted to the First Affiliated Hospital of Xinjiang Medical University in October 2021.Methods The clinical data of proband and family members were collected and analyzed.Whole exon sequencing was conducted for proband's parents,sister and family.Results The proband,male,was 14 years old.He came to the hospital for short stature more than 7 years ago.Full-length X-ray of the of both lower limbs showed that the bilateral acetabulums were shallow and elongated with shorter and thicker femur neck,smaller collodiaphyseal angle,large and coarse swelling,smaller ischium and elongated obturator foramen.The bone alignment of the knee joint was reasonable.The bone shapes of the distal femur and the proximal epiphysis of the tibia-fibula were irregular with uneven density and multiple sclerosis edges.The bone of the ankle joint was well aligned,and the bone of the distal metaphyseal of the bilateral tibia and fibula was irregular with natural density,which was consistent with metaphyseal achondroplasia.Improved gene detection indicated that A heterozygous mutation c.53G>A(guanine>adenine)in the exon region of COL10A1 gene(OMIM No.156500)resulted in amino acid change p.Gly18Glu(glycine>glutamic acid),which had not been reported in China so far.Combined with the clinical manifestations and examination results,the patient was diagnosed as Schmid metaphyseal chondrodysplasia.Conclusions This case extends the mutation site of COL1OA1 gene.Early X-ray and genetic testing are suggested for children suspected as SMCD.