PMC9374118_01
Clinical photograph and radiological findings of the patient. (A) Photograph of the patient's bowed legs at 24 months of age. (B) Plain radiograph of the lower extremities showing bilateral metaphyseal flaring of the distal femur and tibia, associated with varus deformity, at 30 months of age.
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Physical examination revealed significant varus deformities of the bilateral lower extremities ( Figure 1A ) and a waddling gait pattern. X-ray of the lower extremities revealed bilateral tibia vara with metaphyseal beaking and flaring of the proximal tibia, distal tibia, and distal femur ( Figure 1B ).
Genetic analysis of ENPP1 gene and pedigree of the family. (A) Genomic DNA sequences of the patient and his parents exhibiting either homozygous or heterozygous c.783C>G (p.Tyr261*) variant in the ENPP1 gene. (B) Pedigree of the family. The variants identified in the ENPP1 gene are indicated below each individual. The black arrow indicates the proband.
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We identified a homozygous nonsense pathogenic variant in exon 7 of the ENPP1 gene, c.783C>G (p.Tyr261*) ( Figure 2A ). Segregation analysis showed that his parents and sister were heterozygous from the same variants ( Figure 2B ).