Osteopetrorickets: two contradictory patterns-one unifying diagnosis

Abstract

A 5-month-old infant with bone findings on x-ray presented an apparent contradiction including findings of both diffusely dense bones and rickets in the context of a history and laboratory investigation that suggested leukemia. Next generation gene panel sequencing revealed a TCIRG1 mutation which is consistent with autosomal recessive osteopetrosis. The paradoxical x-ray findings underscore a recently elucidated mechanism for the pathogenesis of a TCIRG mutation. This case highlights the importance of recognizing this radiographic, seeming contradictory, association in the context of a confusing clinical presentation. Failure to recognize this pattern promptly may lead to a delay in diagnosis, thus potentially permanent organ failure.

Keywords: Bone; Calcium rickets; Osteosclerosis.

Fig. 1

Frontal chest radiograph at 18 weeks and 6 days of life demonstrate diffusely sclerotic bones with flaring of the costochondral junctions. The humeri metaphysis are frayed and splayed with delayed ossification of the secondary ossification centers

Fig. 2

Magnified view of the right shoulder shows more detail, including periosteal reaction, fraying, and cupping of the metaphysis

Fig. 3

Chest radiograph, including upper abdomen in lordotic projection demonstrates another view of the abnormally flared rib ends. In addition, splenomegaly is apparent in the left upper quadrant

Fig. 4

Axial CT of the lower skull showing diffusely sclerotic bones with absence of diploic spaces