Bone Abstracts

Background: Metaphyseal Chondrodysplasia, Schmid Type(MDS) is a rare autosomal dominant disorder characterized by short stature, coxa vara and bow legs, with radiographs showing diffuse metaphyseal flaring and irregularity of tubular bones. We report a family with MDS from Sri Lanka, where diagnosis was made on family history and typical radiographic features.

Presenting problem: A 5-year-old girl presented with asymmetrical bowing of lower limbs since 2½ years of age. She was the second child of non-consanguineous parents. She was born at term by elective caesarian section due to maternal short stature. Birth-weight and length were between 10th–25th centile, and she appeared healthy. At 2½ years she developed bow legs and had been managed as rickets, but shown no improvement with vitamin D therapy. On examination, her weight and height were below 3rd centile, with height within the mid-parental range (mid-parental height 144 cm). She had bilateral genu varus, with the right knee being more affected than the left. It was noted that the mother was very short (138 cm). She had bilateral knee joint pain for several years, but never been evaluated. The elder sibling had a hip problem detected in early life, which was not followed up. There was no other family history of note.

Clinical management: On investigation of the index child, serum calcium, phosphate and alkaline phosphatase and 25-OH-D levels were normal. Lower limb radiographs showed genu varus with metaphyseal flaring and irregularity. Hip and spine radiographs were normal. Skeletal survey of mother and elder sister showed similar radiographic features, and the elder sister had significant coxa vara. A diagnosis of MDS was made in the mother and two girls based on clinical and radiological findings. The family was counselled, and orthopedic referral done. The elder girl subsequently underwent bilateral hip trochanteric epiphysiodesis. The younger girl had spontaneous improvement of genu varus over time.

Discussion: MDS can present in early childhood with clinical and radiological features similar to rickets. A proper clinical approach can help prevent unnecessary interventions and delay in diagnosis, and help institute timely counselling and management to minimize MDS associated complications.

Disclosure: The authors declared no competing interests.