Osteopoikilosis: pain as a presenting symptom in three family members

Identification of a novel LEMD3 Y871X mutation in a three-generation family with osteopoikilosis and review of the literature

INTRODUCTION

Osteopoikilosis is a rare and benign autosomal dominant genetic disorder, characterized by a symmetric but unequal distribution of multiple hyperostotic areas in different parts of the skeleton. Recent studies have reported loss-of-function mutations in the LEM domain containing 3 (LEMD3) gene, encoding an inner nuclear membrane protein, as a cause of osteopoikilosis.

METHODS

We investigated LEMD3 gene in a three-generation family from China, with six patients affected with osteopoikilosis. Peripheral blood samples were collected from family members and 100 healthy controls. All exons of the LEMD3 gene and adjacent exon-intron sequences were amplified by PCR and subsequently sequenced.

RESULTS

A novel heterozygous c.2612_2613insA (p.Y871X) mutation in exon 13 of LEMD3 was identified, which resulted in a frame shift predicted to generate a premature stop codon at amino acid position 871. The mutation co-segregates with the osteopoikilosis phenotype and was not found in 100 ethnically matched controls.

CONCLUSION

We identified a new mutation in LEMD3 gene, accounting for the familial case of osteopoikilosis. In addition we also review the clinical manifestation, diagnosis and treatment of osteopoikilosis.

Traumatic fracture in a patient with osteopoikilosis

We report a case of traumatic humeral neck fracture occurring in a patient with osteopoikilosis after a motorcycle accident. The radiograph revealed the fracture but also multiple bone lesions. A few years before, the patient had been operated for a maldiagnosed chondrosarcoma of the humeral head. Osteopoikilosis is a rare benign hereditary bone disease, whose mode of inheritance is autosomal dominant. It is usually asymptomatic and discovered incidentally on radiograph that shows the presence of multiple osteoblastic lesions. It can mimic other bone pathologies, in particular osteoblastic metastases. Osteopoikilosis is a diagnosis that should be kept in mind to avoid misdiagnosis, particularly with regard to cancer metastasis. This disorder does not require any treatment and complications are rare. However, there may be associated anomalies that require follow-up.