Hajdu-Cheney syndrome: a case report with review of literature

Imaging approach to pediatric calvarial bulges

Palpable calvarial lesions in children may require multi-modality imaging for adequate characterization due to non-specific clinical features. Causative lesions range from benign incidental lesions to highly aggressive pathologies. While tissue sampling may be required for some lesions, others have a typical imaging appearance, and an informed imaging approach facilitates diagnosis. This review illustrates imaging findings of common and clinically important focal pediatric calvarial bulges to aid the radiologist in narrowing the differential diagnosis and directing appropriate referral. We focus on birth-related lesions, congenital abnormalities, and modeling disturbances (i.e., those that produce a change in calvarial contour early in development), normal variants, and neoplastic lesions with their mimics.

Fracture healing in a mouse model of Hajdu-Cheney-Syndrome with high turnover osteopenia results in decreased biomechanical stability

Notch signaling regulates cell fate in multiple tissues including the skeleton. Hajdu-Cheney-Syndrome (HCS), caused by gain-of-function mutations in the Notch2 gene, is a rare inherited disease featuring early-onset osteoporosis and increased risk for fractures and non-union. As the impact of Notch2 overactivation on fracture healing is unknown, we studied bone regeneration in mice harboring a human HCS mutation. HCS mice, displaying high turnover osteopenia in the non-fractured skeleton, exhibited only minor morphologic alterations in the progression of bone regeneration, evidenced by static radiological and histological outcome measurements. Histomorphometry showed increased osteoclast parameters in the callus of HCS mice, which was accompanied by an increased expression of osteoclast and osteoblast markers. These observations were accompanied by inferior biomechanical stability of healed femora in HCS mice. Together, our data demonstrate that structural indices of bone regeneration are normal in HCS mice, which, however, exhibit signs of increased callus turnover and display impaired biomechanical stability of healed fractures.

Surgical management of high-grade lumbar spondylolisthesis associated with Hajdu-Cheney syndrome: illustrative case

BACKGROUND

Hajdu-Cheney syndrome (HCS) is a rare connective tissue disorder characterized by severe bone demineralization. In the spine, it is associated with the early onset of severe osteoporosis and can cause spondylolisthesis. Spinal instrumentation in the setting of severe osteoporosis is challenging because of poor resistance of vertebrae to biomechanical stress.

OBSERVATIONS

A 59-year-old woman with known idiopathic HCS presented with a grade 4 L5-S1 spondylolisthesis and right L5 pedicle fracture associated with a left L5 pars fracture, causing a progressive L5 radiculopathy that was worse on the left side than the right side and bilateral foot drop. The authors performed decompressive lumbar surgery, which included a complete L5 laminectomy and resection of the left L5 pedicle. This was followed by multilevel lumbosacral instrumentation using cement-augmented fenestrated pedicle screws as well as transdiscal sacral screws and bilateral alar-iliac fixation. Postoperatively, the radicular pain resolved, and the left foot drop partially recovered.

LESSONS

Stabilization of high-grade spondylolisthesis in the setting of bone demineralization disorders is challenging. The use of different instrumentation techniques is important because it increases biomechanical stability of the overall instrumentation construct.

Relevance of Notch Signaling for Bone Metabolism and Regeneration

Notch1-4 receptors and their signaling pathways are expressed in almost all organ systems and play a pivotal role in cell fate decision by coordinating cell proliferation, differentiation and apoptosis. Differential expression and activation of Notch signaling pathways has been observed in a variety of organs and tissues under physiological and pathological conditions. Bone tissue represents a dynamic system, which is constantly remodeled throughout life. In bone, Notch receptors have been shown to control remodeling and regeneration. Numerous functions have been assigned to Notch receptors and ligands, including osteoblast differentiation and matrix mineralization, osteoclast recruitment and cell fusion and osteoblast/osteoclast progenitor cell proliferation. The expression and function of Notch1-4 in the skeleton are distinct and closely depend on the temporal expression at different differentiation stages. This review addresses the current knowledge on Notch signaling in adult bone with emphasis on metabolism, bone regeneration and degenerative skeletal disorders, as well as congenital disorders associated with mutant Notch genes. Moreover, the crosstalk between Notch signaling and other important pathways involved in bone turnover, including Wnt/β-catenin, BMP and RANKL/OPG, are outlined.

Interfrontal Bone Among Inbred Strains of Mice and QTL Mapping

The interfrontal bone (IF) is a minor skeletal trait residing between the frontal bones. IF is considered a quasi-continuous trait. Genetic and environmental factors appear to play roles in its development. The mechanism(s) underlying IF bone development are poorly understood. We sought to survey inbred strains of mice for the prevalence of IF and to perform QTL mapping studies. Archived mouse skulls from a mouse phenome project (MPP) were available for this study. 27 inbred strains were investigated with 6–20 mice examined for each strain. Skulls were viewed dorsally and the IF measured using a zoom stereomicroscope equipped with a calibrated reticle. A two generation cross between C3H/HeJ and C57BL/6J mice was performed to generate a panel of 468 F2 mice. F2 mice were phenotyped for presence or absence of IF bone and among mice with the IF bone maximum widths and lengths were measured. F2 mice were genotyped for 573 SNP markers informative between the two strains and subjected to linkage map construction and interval QTL mapping. Results: Strain dependent differences in the prevalence of IF bones were observed. Overall, 77.8% or 21/27, of the inbred strains examined had IF bones. Six strains (C3H/HeJ, MOLF/EiJ, NZW/LacJ, SPRET/EiJ, SWR/J, and WSB/EiJ) lack IF bones. Among the strains with IF bones, the prevalence ranged from 100% for C57BL/6J, C57/LJ, CBA/J, and NZB/B1NJ and down to 5% for strains such as CAST/Ei. QTL mapping for IF bone length and widths identifies for each trait one strong QTL detected on chromosome 14 along with several other significant QTLs on chromosomes 3, 4, 7, and 11. Strain dependent differences in IF will facilitate investigation of genetic factors contributing to IF development. IF bone formation may be a model to understand intrasutural bone formation.

Congenital Glaucoma: a Novel Ocular Manifestation of Hajdu-Cheney Syndrome

Hajdu-Cheney Syndrome (HSC) is a rare multisystem disease in which the phenotype involves acro-osteolysis, severe osteoporosis, short stature, wormian bones, facial dysmorphism, central neurological abnormalities, cardiovascular defects, and polycystic kidneys. We describe an infant with severe manifestations of HCS in whom congenital glaucoma was a significant early feature, which has not been reported to date. HCS cases reported to date have involved truncating mutations in exon 34 of NOTCH2 upstream the PEST domain that lead to the development of a truncated and stable NOTCH2 protein which upregluates notch signaling. We describe a hitherto undescribed missense mutation that is predicted to be pathogenic, with functional characterization remaining to be performed. Serpentine fibula-polycystic kidney syndrome (SFPKS) is allelic to HCS and commonly associated with missense NOTCH2 mutations. Our patient provides new ophthalmological manifestations of HCS and provides insight into the potential role of notch signaling in the anterior chamber development.

Digital radiomorphometric analysis of the frontal sinus and assessment of the relation between persistent metopic suture and frontal sinus development

OBJECTIVES

This study aimed to establish the frequency of the frontal sinus (FS) aplasia, to compare metopic and nonmetopic series and thus to assess the relationship between the preservation of metopic suture and FS development.

MATERIALS AND METHODS

FSs were investigated in 230 dry skulls of adult males distributed into control (137) and metopic (93) series. They were visualized through industrial digital radiography.

RESULTS

In the control series, the FS aplasia was observed in 12.41% of the skulls, and it was mostly unilateral (8.76%) than bilateral (3.65%). The left-sided aplasia (5.11%) slightly prevailed over the right-sided one (3.65%). In the metopic series, the aplasia was observed with a frequency of 19.35%, and the bilateral aplasia (7.53%) was rarer that the unilateral one (11.83%), while the right-sided aplasia was clearly predominant (9.68%) compared to the left-sided one (2.15%).

DISCUSSION

The significant differences between both series showed a tendency for the persistence of metopic suture to be frequently related with FS underdevelopment in the vertical plate of the frontal bone, but in cases of pneumatization, it was preferentially on the left side. Taking into account that the cranial hypertension leads to suture diastasis and hinders development of the FS, it could be suggested that persistence of the metopic suture along with underdevelopment of the FS in nonsyndromic adults could be an expression of an elevated intracranial pressure during early development as an after-effect of certain condition.

Foot Deformities in Hajdu-Cheney Syndrome: A Rare Case Report and Review of the Literature

Introduction:

Hajdu-Cheney syndrome (HCS) is a rare autosomal dominant disease characterized by acroosteolysis, wormian skull bones with persistent skull sutures, premature loss of teeth, micrognathia, short stature, hypermobility of the joints, neurologic manifestations such as basilar invagination with subsequent paresthesia, hearing loss, and speech alterations, and osteoporosis with tendency to pathologic fractures of long bones and vertebrae as well as painful hands and feet. Very few cases have been earlier reported in the literature.

Case Report:

We report a case of a 50-year-old female with bilateral foot deformities as a manifestation of the rare genetic disorder HCS. Surgical management of the left foot consisted of Morton’s neuroma excision and Weil osteotomy with proximal interphalangeal joint resection and Kirschner wire fixation of the second and third metatarsophalangeal (MTP) joints. Recurrent subluxation of the left second MTP joint was observed at 5-week follow-up. The right foot was treated similarly 7weeks after the initial operation. The post-operative course of the right foot was complicated by bone resorption and nonunion of the second and third metatarsal Weil osteotomies.

Conclusion:

Management of complex foot deformities associated with HCS can be challenging and have not previously been described in the literature. Underlying bone and connective tissue abnormalities intrinsic to the syndrome may increase the risk of recurrence after surgical correction. Consideration should be given to such post-operative complications when treating foot deformities in a patient with HCS.

Extreme proximal junctional kyphosis-a complication of delayed lambdoid suture closure in Hajdu-Cheney syndrome: a case report and literature review

PURPOSE

To describe the manifestations, surgical treatment, and potential complications of Hajdu-Cheney syndrome (HCS), and the management of these complications.

METHODS

The clinical presentation, management and outcome of HCS with severe osteoporosis and open skull sutures is presented, together with a literature review.

RESULTS

A 20-year-old female with HCS underwent posterior occipitocervical fusion for symptoms of progressive basilar invagination. Because of delayed lambdoid suture closure, the stiff fusion construct lead to increased suture distraction, most notably in the upright (suture-open) position, with relief in the supine (suture-closed) position. This was successfully remedied with extension of the fusion construct anteriorly over the skull vertex to the frontal bones.

CONCLUSIONS

In patients with HCS and other conditions with delayed suture closure, the surgeon must be cognizant of the presence of mobility at the suture lines, and consider extending the fusion construct anteriorly over the skull vertex up to the frontal bones. Because of significant osteoporosis in these syndromes, multiple fixation points and augmentation with bone graft are important principles.

Acro-osteolysis

Acro-osteolysis is an osteolysis of the distal phalanges of the hands and feet and can affect the terminal tuft or the shaft of the distal phalanx (transverse or band acro-osteolysis). It is often associated with distal digital ischemia, digital calcinosis, or severe sensory neuropathy. Acro-osteolysis has been associated with a heterogeneous group of disorders, including occupational activities, infections, rheumatic disorders (systemic sclerosis, psoriatic arthritis), endocrinopathies, genetic disorders, and lysosomal storage disorders. Plain radiography is the gold standard for the detection of acro-osteolysis.

Hajdu Cheney Syndrome

Hajdu-Cheney Syndrome is a rare genetic disorder characterised by progressive focal bone destruction. It is known to be an autosomal dominant disorder but there have been reports of sporadic cases as well. Although the disease manifestation is found to begin from birth, it is most often not diagnosed until adolescence or adulthood. It could be due to the rarity of the condition and the variation of the disease manifestation at different age groups. We report a case of Hajdu-Cheney Syndrome in a 26-year-old male who presented with severe periodontitis and premature loss of teeth. The other characteristic features included craniofacial dysmorphism, abnormalities of the digits and dental anomalies. Patients with craniofacial dysmorphism along with dental abnormalities should be thoroughly examined for any underlying systemic disorder. A team of specialists may be able to diagnose this condition before the disease is advanced.

Case Report: Gorham-Stoute Syndrome with Involvement of Majority of Mandible, and Partial Maxillary, Temporal and Zygomatic Bones

The Gorham-Stout syndrome is a rare condition in which spontaneous, progressive resorption of bone occurs. The diagnosis is based on clinical, radiological and histopathological findings after excluding other etiologies and as a result it is often delayed. We present the case of a 21-year-old male diagnosed with Gorham-Stout syndrome with involvement of the majority of the mandible, partial involvement of right maxillary, temporal and zygomatic bones and discuss its diagnostic and therapeutic features.