Buschke-ollendorff syndrome: report of a case and interpretation of the clinical phenotype as a type 2 segmental manifestation of an autosomal dominant skin disease

A case of Myhre syndrome mimicking juvenile scleroderma

BACKGROUND

Myhre syndrome is a genetic disorder caused by gain of function mutations in the SMAD Family Member 4 (SMAD4) gene, resulting in progressive, proliferative skin and organ fibrosis. Skin thickening and joint contractures are often the main presenting features of the disease and may be mistaken for juvenile scleroderma.

CASE PRESENTATION

We report a case of a 13 year-old female presenting with widespread skin thickening and joint contractures from infancy. She was diagnosed with diffuse cutaneous systemic sclerosis, and treatment with corticosteroids and subcutaneous methotrexate recommended. There was however disease progression prompting genetic testing. This identified a rare heterozygous pathogenic variant c.1499 T > C (p.Ile500Thr) in the SMAD4 gene, suggesting a diagnosis of Myhre syndrome. Securing a molecular diagnosis in this case allowed the cessation of immunosuppression, thus reducing the burden of unnecessary and potentially harmful treatment, and allowing genetic counselling.

CONCLUSION

Myhre Syndrome is a rare genetic mimic of scleroderma that should be considered alongside several other monogenic diseases presenting with pathological fibrosis from early in life. We highlight this case to provide an overview of these genetic mimics of scleroderma, and highlight the molecular pathways that can lead to pathological fibrosis. This may provide clues to the pathogenesis of sporadic juvenile scleroderma, and could suggest novel therapeutic targets.

Sclerosing bone dysplasias

The group of sclerosing bone dysplasia's is a clinically and genetically heterogeneous group of rare bone disorders which, according to the latest Nosology and classification of genetic skeletal disorders (2015), can be subdivided in three subgroups; the neonatal osteosclerotic dysplasias, the osteopetroses and related disorders and the other sclerosing bone disorders. Here, we give an overview of the most important radiographic and clinical symptoms, the underlying genetic defect and potential treatment options of the different sclerosing dysplasias included in these subgroups.

Human Genetics of Sclerosing Bone Disorders

PURPOSE OF REVIEW

The group of sclerosing bone disorders encompasses a variety of disorders all marked by increased bone mass. In this review, we give an overview of the genetic causes of this heterogeneous group of disorders and briefly touch upon the value of these findings for the development of novel therapeutic agents.

RECENT FINDINGS

Advances in the next-generation sequencing technologies are accelerating the molecular dissection of the pathogenic mechanisms underlying skeletal dysplasias. Throughout the years, the genetic cause of these disorders has been extensively studied which resulted in the identification of a variety of disease-causing genes and pathways that are involved in bone formation by osteoblasts, bone resorption by osteoclasts, or both processes. Due to this rapidly increasing knowledge, the insights into the regulatory mechanisms of bone metabolism are continuously improving resulting in the identification of novel therapeutic targets for disorders with reduced bone mass and increased bone fragility.

The Buschke-Ollendorff syndrome: a case report of simultaneous osteo-cutaneous malformations in the hand

BACKGROUND

We describe a male with functionally impairing radial deviation of the thumb who presented to us at 24 years of age. Two sclerotic skin lesions had been excised 7 years before because of consecutive skin contracture. Latest radiological examination showed a spotted pattern consistent with osteopoikilosis.

CASE PRESENTATION

A corrective osteotomy of the thumb was carried out due to the patients discomfort. Facing the simultaneous osteo-cutaneous malformation we postulated a Buschke-Ollendorff syndrome. Buschke-Ollendorff syndrome is a rare autosomal-dominant hereditary disorder of connective tissue with typical osteo-cutaneous manifestations. To explore our hypothesis, biopsies were taken from the affected bone lesions and surrounding skin and soft tissue for histological investigation and genetic testing of the LEMD3 gene was performed on blood of the patient. The histology showed typical changes of the bone architecture and a fibrotic collagenous nodule of the skin. The genetic testing on DNA extracted from peripheral blood leucocytes confirmed a heterozygous loss of function mutation in the LEM domain-containing protein 3 (LEMD3) gene coding for the inner nuclear membrane protein MAN1, which causes osteopoikilosis by antagonizing transforming growth factor β (TGF-β) and bone morphogenetic protein (BMP) signalling.

CONCLUSIONS

In atypical cases of simultaneous occurrence of fibrotic skin lesions and a spotted pattern in the X-ray we recommend the genetic screening of the LEMD3 gene. A correct diagnosis of Buschke-Ollendorff syndrome is necessary to spare patients from expensive investigations and to provide reassurance about the benign nature of the disease.

Buschke-Ollendorff syndrome: a novel case series and systematic review

Buschke-Ollendorff syndrome (BOS) is a rare, often benign, autosomal skin disorder. BOS commonly presents with nontender connective tissue naevi and sclerotic bony lesions (osteopoikilosis [OPK]). Herein, we summarize the presenting features of BOS and potential associations by conducting a systematic review of the literature and summarizing a cohort seen at the Hospital for Sick Children (HSC), Toronto, Canada. PubMed was searched using the following terms: 'BOS'; 'dermatofibrosis lenticularis'; 'OPK'; 'LEMD3'; 'elastoma'; 'collagenoma'. Only case reports were included, without date or language restrictions. Cases were further narrowed to those where patients or their families had a combination of skin and bony lesions, or a positive genetic test. Data were summarized using frequencies. In total, 594 reports were discovered, of which 546 (92%) were excluded. The remaining 48 accounted for 164 cases. Skin lesions were noted in 24% of cases and bony lesions in 20%, while 54% of patients had both. In 1% of cases the diagnosis was made on genetic testing alone. A family history was noted in 92% of cases. All patients with spinal stenosis (2%) or shortened status (7%) had OPK. Six per cent of patients had neurological problems. However, 50% of the cohort from HSC had cognitive delays, and only cases from 2007 onwards reported cognitive delays (the prevalence was 17% among those cases). This review confirms the classical diagnostic features of BOS. In addition, it highlights a previously unreported association between a shortened stature and OPK, as well as a possible association with cognitive delays.

Buschke — Ollendorff syndrome in infant patients

The authors present a clinical and histological description of two clinical cases of a rare inherited disease, Buschke — Ollendorff syndrome. In both cases, the disease was not accompanied by the bone tissue dysplasia but at the same time it was characterized by a clear histological pattern specific of this syndrome. The authors provide literature data and discuss issues related to the pathogenesis and particular features of the clinical picture and diagnostics of the disease.

Late-onset focal dermal elastosis: an uncommon mimicker of pseudoxanthoma elasticum

Late-onset focal dermal elastosis is a rare disorder that presents clinically with the development of small white-to-yellow papules simulating pseudoxanthoma elasticum (PXE) in otherwise healthy adults in the seventh through ninth decades. It is characterized histopathologically by foci of increased normal-appearing elastic tissue in the reticular dermis. The disorder lacks any of the systemic complications of PXE and clinically resembles several other elastic tissue disorders that mimic PXE. We report two cases of late-onset focal dermal elastosis. The first is of a 75-year-old female who presented with symmetrically distributed, 2-5 mm white-to-yellow, discrete and coalescing, non-follicular papules on the posterolateral neck, anterior chest and axillae. The second case involves a 39-year-old female who presented with asymptomatic flesh-colored lesions on the posterior neck, back, antecubital and popliteal fossae, thighs, forearms and wrists. Skin biopsies in each case revealed aggregates of elastic fibers in the reticular dermis without calcification. The differential diagnosis of clinical and histopathologic imitators of PXE is discussed.

Buschke-Ollendorff syndrome with striking phenotypic variation resulting from a novel c.2203C>T nonsense mutation in LEMD3

The Buschke-Ollendorff syndrome (BOS) (MIM 166700) is a rare autosomal dominant disorder with highly variable expression that consists of multiple cutaneous elastic nevi and osteopoikilosis. It may exhibit clinical variations, and in some patients either skin or bone lesions may be absent. Recently it has been demonstrated that the heterozygous loss of function in LEMD3 can result in osteopoikilosis, BOS, and melorheostosis. We have studied three generations in a family with BOS with a variable phenotype. The genetic analyses revealed a heterozygous c.2203C>T nonsense mutation at the LEMD3 locus. The mutation induces a change in the 735 arginine codon to a stop codon. This study shows the wide phenotypic variation in BOS and increases the repertory of mutations described to date in LEMD3.

Osteopoikilosis and multiple exostoses caused by novel mutations in LEMD3 and EXT1 genes respectively--coincidence within one family

BACKGROUND

Osteopoikilosis is a rare autosomal dominant genetic disorder, characterised by the occurrence of the hyperostotic spots preferentially localized in the epiphyses and metaphyses of the long bones, and in the carpal and tarsal bones 1. Heterozygous LEMD3 gene mutations were shown to be the primary cause of the disease 2. Association of the primarily asymptomatic osteopokilosis with connective tissue nevi of the skin is categorized as Buschke-Ollendorff syndrome (BOS) 3. Additionally, osteopoikilosis can coincide with melorheostosis (MRO), a more severe bone disease characterised by the ectopic bone formation on the periosteal and endosteal surface of the long bones 456. However, not all MRO affected individuals carry germ-line LEMD3 mutations 7. Thus, the genetic cause of MRO remains unknown. Here we describe a familial case of osteopoikilosis in which a novel heterozygous LEMD3 mutation coincides with a novel mutation in EXT1, a gene involved in aetiology of multiple exostosis syndrome. The patients affected with both LEMD3 and EXT1 gene mutations displayed typical features of the osteopoikilosis. There were no additional skeletal manifestations detected however, various non-skeletal pathologies coincided in this group.

METHODS

We investigated LEMD3 and EXT1 in the three-generation family from Poland, with 5 patients affected with osteopoikilosis and one child affected with multiple exostoses.

RESULTS

We found a novel c.2203C > T (p.R735X) mutation in exon 9 of LEMD3, resulting in a premature stop codon at amino acid position 735. The mutation co-segregates with the osteopoikilosis phenotype and was not found in 200 ethnically matched controls. Another new substitution G > A was found in EXT1 gene at position 1732 (cDNA) in Exon 9 (p.A578T) in three out of five osteopoikilosis affected family members. Evolutionary conservation of the affected amino acid suggested possible functional relevance, however no additional skeletal manifestations were observed other then those specific for osteopoikilosis. Finally in one member of the family we found a splice site mutation in the EXT1 gene intron 5 (IVS5-2 A > G) resulting in the deletion of 9 bp of cDNA encoding three evolutionarily conserved amino acid residues. This child patient suffered from a severe form of exostoses, thus a causal relationship can be postulated.

CONCLUSIONS

We identified a new mutation in LEMD3 gene, accounting for the familial case of osteopoikilosis. In the same family we identified two novel EXT1 gene mutations. One of them A598T co-incided with the LEMD3 mutation. Co-incidence of LEMD3 and EXT1 gene mutations was not associated with a more severe skeletal phenotype in those patients.

Involvement of Wnt signaling in dermal fibroblasts

Pachydermoperiostosis (PDP) is a rare disease characterized by unique phenotypes of the skin and bone, such as thick skin, implying that it may be caused by dysregulation of mesenchymal cells. The aim of this study is to examine the roles of dermal fibroblasts in the pathogenesis of pachydermia in association with Wnt signaling. The numbers of cultured fibroblasts were compared between healthy donors and PDP patients, and mRNA expression profiles in cultured dermal fibroblasts were examined by DNA microarray analysis and real-time reverse transcription-PCR. DKK1 and beta-catenin protein expressions were also evaluated by immunohistochemistry in the skin. To evaluate the in vivo roles of DKK1 in mice, DKK1 small interfering RNA was injected to the ears. We found that PDP fibroblasts proliferated more than control fibroblasts and that mRNA expression of a Wnt signaling antagonist, DKK1, was much lower in PDP fibroblasts than in normal ones. Consistently, decreased expression of DKK1 in fibroblasts and enhanced expression of beta-catenin were noted in PDP patients. Moreover, recombinant human DKK1 protein decreased the proliferation of dermal fibroblasts. In accord with the above human studies, intradermal injections of DKK1 small interfering RNA into mouse ears increased ear thickness as seen in PDP. Our findings suggest that enhanced Wnt signaling contributes to the development of pachydermia by enhancing dermal fibroblast functions.

Buschke-Ollendorff syndrome

BACKGROUND

Buschke-Ollendorff syndrome is a rare autosomal dominant disease featuring osteopoikilosis and skin lesions. It is caused by genetic mutations in a protein deeply involved in bone and connective tissue morphogenesis.

METHODS

We describe a 39-year-old woman with Buschke-Ollendorff syndrome.

RESULTS

After a minor trauma, radiologic examination of the left ankle of a 39-year-old woman revealed features of osteopoikilosis. Physical examination of the patient showed multiple asymptomatic nodules on both thighs, present since the age of 20 years, which had increased in size and number. Recently, a linear, string-like lesion had appeared on the right thigh.

CONCLUSION

The correct diagnosis of Buschke-Ollendorff syndrome may require a high index of suspicion.

Generalized Nodular Dermatofibrosis in the Absence of Renal Neoplasia in an Australian Cattle Dog

A 13-year-old, spayed, female Australian Cattle Dog had at least a 10-year history of numerous subcutaneous nodules for which fine-needle aspiration and cytologic evaluation were nondiagnostic. Abdominal ultrasound 3.5 months before necropsy detected a small left kidney but no cysts or neoplasms. At gross necropsy, innumerable, firm, round to oval, white, 0.25 to 2 cm masses were detected throughout the subcutaneous tissues of the axial and appendicular skeleton, epimysium of numerous muscles, and parietal peritoneum of the lateral abdominal body wall. The left kidney was approximately half the size of the right, and there was severe bilateral renal medullary (papillary) necrosis. Histologically, the subcutaneous nodules were well-demarcated masses of mature, hypocellular collagen that were consistent with previous reports of nodular dermatofibrosis and renal cystadenomas or cystadenocarcinomas. In addition to diffuse acute medullary necrosis, both kidneys were affected by severe chronic lymphoplasmacytic interstitial nephritis. This is the first known report of nodular dermatofibrosis in a dog without renal cysts, cystadenoma, or cystadenocarcinoma.

Buschke-Ollendorff syndrome: a 32-month-old boy with elastomas and craniosynostosis

A 32-month-old boy with hypotonia, developmental delay, and multiple craniofacial abnormalities including craniosynostosis presented with numerous nonspecific, flesh-colored papules on his right flank. Upon biopsy, these lesions were diagnosed as elastomas. Similar skin lesions were found in the patient's younger brother. The patient's father and brother had osteopoikilotic lesions on radiography, but the patient did not have these findings. None of the reported cases to date have included craniosynostosis in association with Buschke-Ollendorff syndrome. In addition to the case findings, the report also provides a short and current review of the syndrome.

A novel LEMD3 mutation common to patients with osteopoikilosis with and without melorheostosis

Recent studies have reported loss of function mutations in the LEMD3 gene, encoding an inner nuclear membrane protein that influences Smad signaling, as a cause of osteopoikilosis, Buschke-Ollendorff syndrome, and melorheostosis. We investigated LEMD3 in a three-generation family with osteopoikilosis from the Azores, an affected father and daughter from Ireland with osteopoikilosis (the daughter also had melorheostosis), and two other individuals from the UK with isolated melorheostosis. We found a novel C to T substitution at position 2032 bp (cDNA) in exon 8 of LEMD3, resulting in a premature stop codon at amino acid position 678. This mutation co-segregates with the osteopoikilosis phenotype in both the Azorean family and the Irish family. It was not detected in any of the six unaffected family members or in 342 healthy Caucasian individuals. No LEMD3 mutations were detected in the two patients with sporadic melorheostosis. The LEMD3 mutation reported was clearly the cause of osteopoikilosis in the two families but its relationship to melorheostosis in one of the family members is still unclear. Perhaps unsurprisingly in what is a segmental disease, we did not find LEMD3 mutations in peripheral-blood-derived DNA from the two other individuals with sporadic melorheostosis. The nature of the additional genetic and/or environmental influences required for the development of melorheostosis in those with osteopoikilosis requires further investigation.

Loss-of-function mutations in LEMD3 result in osteopoikilosis, Buschke-Ollendorff syndrome and melorheostosis

Osteopoikilosis, Buschke-Ollendorff syndrome (BOS) and melorheostosis are disorders characterized by increased bone density. The occurrence of one or more of these phenotypes in the same individual or family suggests that these entities might be allelic. We collected data from three families in which affected individuals had osteopoikilosis with or without manifestations of BOS or melorheostosis. A genome-wide linkage analysis in these families, followed by the identification of a microdeletion in an unrelated individual with these diseases, allowed us to map the gene that is mutated in osteopoikilosis. All the affected individuals that we investigated were heterozygous with respect to a loss-of-function mutation in LEMD3 (also called MAN1), which encodes an inner nuclear membrane protein. A somatic mutation in the second allele of LEMD3 could not be identified in fibroblasts from affected skin of an individual with BOS and an individual with melorheostosis. XMAN1, the Xenopus laevis ortholog, antagonizes BMP signaling during embryogenesis. In this study, LEMD3 interacted with BMP and activin-TGFbeta receptor-activated Smads and antagonized both signaling pathways in human cells.