Molecular basis of clinical heterogeneity in the Ehlers-Danlos syndrome

Celiprolol: A Unique Selective Adrenoceptor Modulator

Celiprolol is a β-blocker with a unique pharmacologic profile: it is a β1-andrenoceptor antagonist with partial β2 agonist activity. Given this combination of effects, celiprolol may be better described as a selective adrenoreceptor modulator. It has antihypertensive and antianginal properties and is indicated for those uses in various countries around the world. In the United States, however, the proposed indication for this drug will be for the treatment of vascular type Ehlers–Danlos syndrome, a rare connective tissue disorder characterized by fragile arterial structure and an increased risk of life-threatening vascular complications. By reducing heart rate and pulsatile pressure, celiprolol may reduce the mechanical stress on collagen fibers within the arterial wall and be of benefit in patients with vascular type Ehlers–Danlos syndrome. The largest investigation of celiprolol in vascular Ehlers–Danlos syndrome was prematurely terminated due to significant benefit with celiprolol in reducing arterial events in patients with this condition. Celiprolol, therefore, represents a β-blocker that is unique from others in its class in both its pharmacology and clinical applications.

Use of Anti-Inflammatory Medications in Managing Atypical Gingivitis Associated With Hypermobile Ehlers-Danlos Syndrome: A Case Report

BACKGROUND

Ehlers-Danlos syndrome (EDS) is a group of collagen disorders primarily affecting the skin and joints. This case report describes the periodontal management of a case of hypermobile EDS (type III) associated with atypical gingivitis.

METHODS

A 17-year-old Caucasian female with a history of EDS type III presented with erythematous mucogingival lesions. An incisional biopsy was taken. The treatment objective was to control the mucogingival inflammatory lesions. Plaque control measures were followed with anti-inflammatory medications. Prednisone was administered systemically for 3 weeks (first week: 30 mg/day, second week: 15 mg/day, and third week: 5 mg/day), and was followed with topical applications of clobetasol (0.05%) twice daily for 2 weeks. Persistent marginal gingival inflammation was managed with a 3-month course of doxycycline (20 mg) twice/day. The patient was placed on a 3-month maintenance program and monitored for over a year

RESULTS

Histopathology showed multiple granulomas enclosing fragments of crystalline foreign material. Steriodal anti-inflammatory medications partially reduced the size and intensity of the mucogingival lesions. Doxycycline controlled the residual marginal inflammation. A 3-month maintenance interval helped in maintaining the results obtained.

CONCLUSIONS

The collagen disorder may have facilitated the introduction and lodging of foreign material within the gingival tissues, initiating a foreign body reaction. Poor healing associated with EDS excluded surgical excision and necessitated the use of anti-inflammatory medications. A combined approach of plaque control measures along with anti-inflammatory medications was helpful in controlling the mucogingival inflammatory lesions associated with this condition.

The lack of type III collagen in a patient with aneurysms and an aortic dissection

We analyzed 79 consecutive patients with aneurysms and found a patient who lacked type III collagen. Collagen was extracted from the skin, and the lack of type III collagen was determined by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Only 1 of the 79 patients was found to lack type III collagen. This patient was a 55-year-old man who had sustained an abdominal aortic aneurysm and aortic dissection. He did not show any of the typical clinical symptoms of Ehlers-Danlos syndrome type IV, such as hyperextensible skin and joints. He had none of the usual risk factors nor any clear family history of the syndrome. Furthermore, his collagen fibrils demonstrated a homogeneous appearance. This case may represent a new form of type III collagen deficiency.

Ehlers-Danlos syndrome type IV: a heterogeneous disease

The Ehlers-Danlos syndrome is an inherited disorder of connective tissue, consisting of at least 10 different clinical subtypes. Type IV Ehlers-Danlos syndrome is an autosomal dominant condition characterized by the joint and dermal manifestations as in other forms of the syndrome but also by the proneness to spontaneous rupture of bowel and large arteries. The authors describe their experience with three patients presenting type IV Ehlers-Danlos syndrome: the first presented with several subsequent arterial ruptures, the second with multiple aneurysms, and the third with a dissection of the internal carotid artery. Clinical features, incidence, diagnosis, and treatment of the syndrome are discussed.

Ehlers-Danlos syndrome: recent advances and current understanding of the clinical and genetic heterogeneity

The Ehlers-Danlos syndrome (EDS) is a heterogeneous group of generalized connective tissue disorders, the major manifestations of which are skin fragility, skin hyperextensibility, and joint hypermobility. The clinical and molecular definition of more than ten types of EDS has, more than ever, emphasized the importance of correct diagnosis because the natural history and mode of inheritance differ among the types. Unfortunately, much of the older literature does not differentiate among the types clearly, and in some instances the life-threatening complications of EDS type IV may be cited as characteristic of the syndrome as a whole. Heterogeneity in EDS began to be appreciated about 30 years ago when the core of the modern classification was developed by Barabas. Since then it was extended by Beighton et al, and then amplified with the insights provided by biochemical and molecular genetic studies. Clinical studies were sufficient initially to distinguish five types of EDS; biochemical studies identified four additional types, EDS type VI, EDS type VII, EDS type IX, and EDS type X, whereas clinical criteria distinguished EDS type VIII. In the following sections, the clinical manifestations of the different forms of EDS are summarized and the known biochemical and molecular genetic features are emphasized.

Emergency operation for thoracic aortic aneurysm caused by the Ehlers-Danlos syndrome

Two patients were treated emergently for impending ruptured thoracic aortic aneurysms caused by type IV Ehlers-Danlos syndrome. One patient had typical physical evidence of type IV Ehlers-Danlos syndrome. The other patient had a normal phenotype. Type IV Ehlers-Danlos syndrome was diagnosed by electrophoresis of the collagen extracted from the skin. The clinician must be aware of the variations in presentation of type IV Ehlers-Danlos syndrome.

Structural aberration of the rough endoplasmic reticulum and melanosome compartmentalization in long-term cultures of melanocytes from vitiligo patients

Long-term cultures of melanocytes were established from 14 subjects with vitiligo and from five normal controls and analyzed ultrastructurally. Cultured melanocytes from 78.6% of the vitiligo patients demonstrated abnormalities that consisted of 1) dilation of the rough endoplasmic reticulum (RER), 2) circular RER profiles, and/or 3) membrane bound compartments of melanosomes. Cultured melanocytes from control subjects were predominantly normal with only one of the normal cultures demonstrating minimal circular RER profiles. The three unique abnormal structures in cultured vitiligo melanocytes were not always concomitantly expressed and could not be associated with any specific clinical feature of vitiligo. Quantitative analysis of the RER demonstrated that the profiles of dilated RER in cultured vitiligo melanocytes expressed a significant 1.5-2.8-times increase in mean cisternal area over cultured control melanocytes (i.e., 5.41-9.92 microns 2 versus 3.53 microns 2, respectively). The cisterna of the dilated RER profiles frequently contained floccular material that appeared to originate from the ribosomes, an indication that the floccular material may be translation products. The dilation of RER in melanocytes from the same patient persisted through repeated subculturing for up to 14.75 months. Epidermal melanocytes in biopsied skin from a patient whose cultured melanocytes were aberrant also demonstrated dilated and circular RER profiles. These results demonstrate that melanocytes from most vitiligo patients express an innate defect when cultured. Although this defect does not appear to be cytotoxic in vitro, this abnormality may be the primary defect that elicits melanocyte destruction in vivo.

Syndromology: an updated conceptual overview. X. References

Part X is the reference section for Parts I through VIII which appeared in the four previous issues of the journal and Part IX which appears in this issue. The reference section itself is divided into two parts. The first part provides general references of selected topics for the interested reader. The second part consists of an alphabetical listing of all references cited in Parts I through IX.

Inherited disorders of collagen gene structure and expression

As a result of investigations completed during the last 15 years, the molecular bases of most form of osteogenesis imperfecta (OI) and of some forms of the Ehlers-Danlos syndrome (EDS) are now known. Most forms of OI result from point mutations in the genes (COL1A1 and COL1A2) that encode the chains of type I procollagen or mutations that affect the expression of these genes. Less frequently, mutations that affect the size of the chain can also result in these phenotypes. The phenotypic presentation appears to be determined by the nature of the mutation, the chain in which it occurs, and, for point mutations, the position of the substitution and the nature of the substituting amino acid in the protein product. Similar mutations in the gene (COL3A1) that encodes the chains of type III procollagen result in the EDS type IV phenotype. Mutations which result in deletion of the cleavage site for the aminoterminal procollagen protease result in the EDS type VII phenotype and other mutations which affect the structure of the triple-helical domain by deletions and alter the conformation of the substrate at the site of proteolytic conversion can produce mixed phenotypes. Alterations in post-translational processing of collagenous proteins can result in the EDS type VI and EDS type IX phenotypes. Linkage analysis and study of type II collagen proteins from individuals with a variety of skeletal dysplasias suggest that similar mutations in these genes also result in clinically apparent phenotypes. Mutations in the majority of the 20 known collagen genes have not yet been identified.

Ehlers-Danlos syndrome type IV: a subset of patients distinguished by low serum levels of the amino-terminal propeptide of type III procollagen

Serum levels of procollagen type III aminopropeptide (P-III-NP), a peptide released during conversion of type III procollagen to collagen, were abnormally low in six of 10 patients with Ehlers-Danlos syndrome (EDS) type IV (arterial-ecchymotic type) and low-normal in 4. The serum P-III-NP levels correlated with the amount of type III procollagen secreted by the patients' cultured fibroblasts. Serum P-III-NP determination is a simple test that identifies a major subgroup of patients with this life-threatening, dominantly inherited connective tissue disorder and may be especially helpful in making the diagnosis in children.

Separation methods for the study of collagen and treatment of collagen disorders

Liquid chromatographic and electrophoretic methods applicable to the separation of collagen and its fragments are reviewed. Special attention is paid to the separation of both stabile and labile crosslinking elements. Identification procedures exploiting the mapping of either collagen alpha-chains or of cyanogen bromide fragments are discussed. These methods can be used for diagnosing inborn errors of collagen metabolism using bioptic or necroptic samples. Analysis of urinary hydroxyproline-containing peptides or the determination of peptidically bound pyridinoline is suitable for measuring the intensity of collagen metabolism.

Familial aortic dissecting aneurysm

A family is described in which nine members over two generations had an aortic dissecting aneurysm or aortic or arterial dilation at a young age. The family has been followed up since 1977 after the death of a second teenager from a kindred of 11. None of the patients had the Marfan syndrome or a history of systemic hypertension. Three members died of ruptured aortic dissecting aneurysm and acute hemopericardium at 14, 18 and 24 years of age, respectively; a fourth member died suddenly at age 48 years, a few years after aortic repair for aneurysmal dilation. One member underwent surgical repair of an ascending aortic dissecting aneurysm at age 18 years and is still alive. Four members are currently under close medical observation for aortic or arterial dilation. Histologic examination of the aortic wall at autopsy or surgery in three patients revealed a loss of elastic fibers, deposition of mucopolysaccharide-like material in the media and cystic medial changes. Types I and III collagen from cultured fibroblasts appeared normal on gel electrophoresis. Results of indirect immunofluorescent studies of the elastin-associated microfibrillar fiber array in skin and fibroblast culture from multiple family members were also normal. This dramatic familial cluster of aortic dissecting aneurysm and aortic or arterial dilation suggests a genetically determined disease of autosomal dominant inheritance although the basic defect remains unknown.

Cutaneous wound healing in Ehlers-Danlos syndrome

Wound healing in five dogs and five cats affected with a connective tissue dysplasia resembling Ehlers-Danlos syndrome of humans was compared with wound healing in 10 nonaffected animals. Six skin incisions on the lateral aspects of the thorax and abdomen of each animal were sutured and assessed daily for 75 days for evidence of healing. All wounds in nonaffected dogs, affected cats, and nonaffected cats healed by first intention. Three incisions in affected dogs had dehiscence of all or part of the incision line and healed by granulation, contraction, and epithelialization. Biopsies taken at 3, 6, 9, 12, 15, and 75 days were compared histologically to determine if there were any differences in rates of healing between affected and nonaffected animals. Epidermal thickening and scab formation were noted at days 3 and 6 in both affected and nonaffected animals. Infiltration with mononuclear cells and fibroplasia steadily increased from day 6 to day 15 in all groups. Collagen fibril formation was evident by day 9. At day 75, incision sites were recognized by fine, more compact collagen bundles and lack of adnexal structures, as compared with the adjacent dermis in both affected and nonaffected animals. Although delayed wound healing has been reported to be a complication of Ehlers-Danlos syndrome in humans, using clinical and histologic criteria, wound healing in dogs and cats with Ehlers-Danlos syndrome appears to be similar to nonaffected animals.

Ehlers-Danlos syndrome: a new oculo-scoliotic type with associated polyneuropathy?

Two siblings born to consanguineous Bedouin parents and grandparents are reported with the phenotypic features of Ehlers-Danlos Syndrome (EDS), type VI. In addition, the affected individuals have a polyneuropathy as confirmed by nerve conduction velocity, electromyographic and muscle biopsy studies. We propose that this clinical combination represents a distinct type of EDS.

The Ehlers-Danlos syndrome: recognition, characterization, and importance of a milder variant of the classic form. A preliminary study

The diagnosis of Ehlers-Danlos syndrome is based on the clinical criteria of joint hypermobility, increased skin extensibility, abnormal scarring, and easy bruisibility. The literature reports this syndrome as rare, yet our experience dictated to the contrary. The present study of the prevalence of Ehlers-Danlos syndrome in a general dermatology population revealed (1) a milder variant of the classic mitis form of Ehlers-Danlos syndrome was common and present in 9% of the population studied, (2) these patients could be easily identified by the use of a defined clinical scoring system, and (3) a statistically significant association existed between clinical findings in Ehlers-Danlos syndrome and electron microscopic collagen abnormalities. The identification of this syndrome may be important prognostically in patients with diseases or conditions in which collagen plays a major role, such as joint disease (dislocations), bruising disease (pigmented purpura), and potentially scarring diseases (acne, patients undergoing cutaneous surgery).

Impaired secretion of type III procollagen in Ehlers-Danlos syndrome type IV fibroblasts: correction of the defect by incubation at reduced temperature and demonstration of subtle alterations in the triple-helical region of the molecule

The amount of type III procollagen secreted by fibroblasts from two patients with type IV Ehlers-Danlos syndrome is reduced to 25% and 20%, respectively, of that of control cells after incubation at 37 degrees C, but reverts to 70% and 110% when cells are incubated at 32 degrees C. The type III procollagen molecules secreted only at the lower temperature are of normal size but apparently contain different mutations which disrupt the triple-helical region and lower the thermal stability of the molecule. These data suggest that subtle mutations in the pro alpha 1(III)-chains produce Ehlers-Danlos syndrome type IV by disrupting the triple-helical region of the molecule, lowering its thermal stability, and thus impairing its secretion. At the lower temperature, stabilization of the defective molecules result in more efficient secretion. This approach may be useful for the characterization of other unstable collagens.

Spontaneous carotid-cavernous fistula and multiple arterial dissections in type IV Ehlers-Danlos syndrome. Case report

A 43-year-old woman without phenotypic expression of Ehlers-Danlos syndrome developed a spontaneous unilateral carotid-cavernous fistula (CCF). Attempts at balloon occlusion of the CCF were unsuccessful, and caused multiple arterial dissections and lacerations eventually leading to massive retroperitoneal hemorrhage and death. The CCF was demonstrated during postmortem studies. In addition, the patient had independent dissections of the internal carotid artery at the site of the fistula and an intracavernous aneurysm of the contralateral internal carotid artery. Despite widespread dissections, the major arteries showed only mild histological abnormalities. Morphometric analysis of collagen from the aorta revealed an increase in large-sized fibers, consistent with deficiency of Type III collagen.