β-Mannosidosis with Angiokeratoma Corporis Diffusum

Beta-mannosidosis is a lysosomal disorder which is caused by a deficiency of beta-mannosidase. This disorder was first described in goats. Twelve human cases have already been reported. We present the first case in Japan in whom the diagnosis was reached from angiokeratoma corporis diffusum. Futhermore, mental retardation, hearing loss, and renal failure were also detected. Pseudoxanthoma elasticum was also present, but whether it is a complication of beta-mannosidosis or not remains unknown. The activity level of beta-mannosidase in the patient's plasma was only 2% of the normal range, while that in the patient's mother was 40%. We suggest that beta-mannosidosis should be one of the differential diagnoses when lysosomal enzyme disorders are suspected in cases of angiokeratoma corporis diffusum.

White Fibrous Papulosis of the Neck: A Chinese Case

A 48-year-old man who presented with papules on his neck was reported. The patient had multiple, discrete, non-follicular papules on the neck that were round-to-oval, 2--3 mm in diameter and pale. They had remained entirely asymptomatic. On histologic examination, there were circumscribed areas of thickened collagen bundles in the papillary to mid-dermis. This clinical and histologic picture suggested the diagnosis of "white fibrous papulosis of the neck". As far as we are aware, this is the first report of the condition from China.

Choroidal changes associated with Bruch membrane pathology in pseudoxanthoma elasticum

PURPOSE

To investigate the impact of Bruch membrane pathology on the choroid in pseudoxanthoma elasticum (PXE).

DESIGN

Monocenter cross-sectional prospective case series.

METHODS

The study included 61 eyes of 51 patients with PXE and 54 eyes of 54 normal subjects. The diagnosis of PXE was based on skin biopsy, genetic analysis or both. Eyes with PXE were subdivided into 3 groups: eyes without choroidal neovascularization (CNV) or chorioretinal atrophy (Group 1); eyes with active or fibrotic CNV (Group 2); and eyes with chorioretinal atrophy only (Group 3). Choroidal thickness was measured using enhanced-depth imaging optical coherence tomography (EDI-OCT).

RESULTS

Compared to controls (331 μm ± 24; mean ± 95% CI), mean subfoveal choroidal thickness in eyes of patients with PXE was significantly reduced within all 3 groups (Group 1: 243 μm ± 29; Group 2: 184 μm ± 28; Group 3: 104 μm ± 28; P < 0.001). Associated structural changes included apparent loss of small choroidal vessels. The difference of PXE compared to control eyes was largest close to the optic disc and approximated the level of controls toward the periphery. Within the PXE subgroups, eyes without CNV or chorioretinal atrophy (Group 1) showed the least reduction of choroidal thickness, while it was most pronounced in Group 3.

CONCLUSIONS

The results indicate that changes of Bruch membrane can be associated with choroidal alterations, which are most pronounced in the presence of advanced disease. A role of Bruch membrane in choroidal homeostasis may reflect a possible contribution of Bruch membrane alterations to CNV and geographic atrophy development in age-related macular degeneration.

Geographic chorioretinal atrophy in pseudoxanthoma elasticum

PURPOSE

To describe a series of patients with geographic atrophy independent of choroidal neovascularization (CNV) in pseudoxanthoma elasticum and to report progression over time.

DESIGN

Retrospective observational case series.

METHODS

Records of all Vanderbilt Eye Institute patients with pseudoxanthoma elasticum and at least 1 set of color fundus photographs were reviewed (41 eyes of 21 patients). Fluorescein angiography, fundus autofluorescence, and optical coherence tomography images were reviewed, when available. In patients with geographic atrophy and at least 1 year of follow-up, atrophy was measured using fundus photographs. Main outcome measures included incidence of geographic atrophy, progression over time, and macular features associated with development or progression of geographic atrophy.

RESULTS

Eight eyes (20%) of 5 patients had geographic atrophy independent of CNV. Progression was documented in 6 eyes of 4 patients followed for at least 1 year (mean 3.5 years). Mean initial and final area was 2.9 and 9.5 mm(2), respectively, and growth rate was 1.7 mm(2) per year. Of the 6 eyes, 3 had a final visual acuity of 20/20 and the other 3 ranged from 20/150 to 20/400. All 8 eyes had pattern dystrophy, and 5 had linear pigment deposits that appeared to predict development or growth of atrophy.

CONCLUSIONS

Isolated geographic atrophy independent of CNV can develop in pseudoxanthoma elasticum, causing significant vision loss. Linear pigmented pattern dystrophy appears to predate geographic atrophy. Progression is similar to age-related macular degeneration. Recognition of this feature is important, especially if therapies to slow or reverse geographic atrophy become available.

Pseudoxanthoma elasticum confirmed by genetic analysis but not by skin biopsy: a case report and review of the literature

In patients with angioid streaks, additional investigations are useful to identify underlying systemic disease, unless age and short peripapillary streaks are indicative of senile streaks as an isolated abnormality. In middle-aged or young adults with angioid streaks and no obvious systemic disease, the possibility of a hemoglobulinopathy or pseudoxanthoma elasticum (PXE) as etiologic entities should be investigated. Hemoglobinopathies can be excluded based on blood screening and the absence of typical ocular fundus changes, such as retinal vessel tortuosity. This allows making a presumed clinical diagnosis of PXE in patients with angioid streaks, based on exclusion of a hemoglobinopathy, and on the presence of extensive angioid streaks, peau d'orange, crystalline bodies and comet tail lesions. For confirmation of PXE, the gold standard was dermatologic examination and skin biopsy, but since the last decade molecular diagnosis is available. In rare cases, PXE can be diagnosed using molecular techniques in patients with apparently normal skin and negative skin biopsies, as demonstrated in this case and another case published in 2011.

Papillary dermal elastosis

We recently came across the article "Papillary dermal elastosis" by Newlove et al published in the October 2011 edition of Dermatology Online Journal. In this paper, the authors described what they interpreted to be the second case of papillary dermal elastosis, an entity we had first identified in 2009. Upon further reading of their histopathologic and clinical description, we believe this case is more consistent with the diagnosis of pseudoxanthoma elasticum-like papillary dermal elastolysis (PXE-PDE).

Pseudoxanthoma elasticum: progress in diagnostics and research towards treatment : Summary of the 2010 PXE International Research Meeting

Pseudoxanthoma elasticum (PXE), a prototypic heritable disorder with ectopic mineralization, manifests with characteristic skin findings, ocular involvement, and cardiovascular problems. The classic forms of PXE are due to loss-of-function mutations in the ABCC6 gene, which encodes ABCC6, a putative transmembrane efflux transporter expressed primarily in the liver. While considerable progress has recently been made in understanding the molecular genetics and pathomechanisms of PXE, no effective or specific treatment is currently available for this disorder. PXE International, the premiere patient advocacy organization, organized a workshop in November 2010 to assess the current state of diagnostics and research to develop an agenda towards treatment of PXE. This overview summarizes the progress in PXE research, with emphasis on molecular therapies for this, currently intractable, disorder.

Relationship between ankle brachial index and arterial remodeling in pseudoxanthoma elasticum

OBJECTIVES

Pseudoxanthoma elasticum (PXE) is an inherited metabolic disease characterized by elastic fiber fragmentation and calcification in the cutaneous, ophthalmologic, and vascular tissues. Cardiovascular manifestations such as peripheral arterial disease (PAD) are frequent in PXE. Because of the changes in the elastic properties and medial calcification of the arterial wall in PXE, the impact of the arterial remodeling on the ankle brachial index (ABI), a well-established diagnostic method for the detection and follow-up of PAD, remains to be determined in this disease.

METHODS

This was a cross-sectional, comparative, open study, which took place at the PXE Consultation Center, University Hospital of Angers. The subjects were 53 patients (mean age, 49 ± 14 years; 35 females) with PXE clinically proven on the basis of established criteria (skin changes, angioid streaks, and skin biopsy). The ABI at rest, symptoms of intermittent claudication (IC), carotid intima-media thickness (IMT), carotid-femoral pulse wave velocity (c-f PWV), compliance (CC), and β stiffness index were measured in a single-center cohort.

RESULTS

Forty-five percent of the PXE patients had an ABI ≤0.90, but only one patient had an ABI >1.40. IC was found in 23% of the patients with an ABI ≤0.90. There were no significant differences between the patients with a low and normal ABI in terms of IMT (P = .566) or β stiffness index (P = .194), but differences were significant for c-f PWV (P = .010) and CC (P = .011). Adjusted multivariate linear regression for the Framingham-Laurier score showed that patients with a low ABI had less compliant carotid arteries (B = 0.318, P = .039).

CONCLUSIONS

PAD detected by a low ABI is very frequent in PXE, although with limited prevalence of symptomatic claudication. Unexpectedly, ABI was low in such calcifying PAD and associated with lower CC, independently of atherosclerosis risk factors. These findings demonstrate that PXE represents a unique monogenic model of PAD in which the specific arterial wall remodeling could change the diagnostic value of the ABI to detect PAD.

Pseudoxanthoma elasticum: clinical, histologic, and genetic studies--a report of two sisters

CASE 1: A 24-year-old black woman was referred to our clinic in September 1999 by the department of dermatology. She was referred to confirm the diagnosis of pseudoxanthoma elasticum (PXE). Her medical history was normal. Dermatologic examination revealed confluent papules that gave the skin a "plucked chicken" appearance on the flexural surfaces in the neck, axillae, clavicle, thigh, and periumbilical area (Figure 1). The patient stated that the changes in her skin had begun in the periumbilical region at about 5 years of age and had since been slowly progressive. Physical examination showed brownish black pigmentation on the left side of the face, left eyelid, and left sclera, which was diagnosed as Nevus of Ota (Figure 2). Her visual acuity was 20/10 in both eyes, with no afferent pupillary defect. Intraocular pressure in both eyes was normal. Slit lamp examination showed no abnormalities. Findings from fundus examination revealed angioid streaks that formed an incomplete ring around the optic disc and anteriorly radiated toward the equator of the globe, multiple calcified drusen-like structures, and "peau d'orange" changes. Skin biopsy (skin tissue from the neck) was taken and the diagnosis of PXE was confirmed. Histopathologic findings revealed calcification of the elastic fibers and abnormalities of the collagen (Figure 3). The patient was not known to have sickle cell anemia or sickle cell trait, and her blood pressure levels had never elevated. Other systemic causes of angioid streaks were excluded by findings from extensive laboratory examination. Her relatives were asked to come in for examination but lived far away. One of the patient's sisters lived in Kinshasa, Africa, however, and is presented in case 2. CASE 2: The 27-year-old sister of the previous patient was examined on April 19, 2000. At examination, she was found to have PXE. Her medical history was significant for systemic hypertension since 1998 and genital hemorrhage. She underwent an ablation of a cyst of her left ovary in 1988. Her ocular history was unremarkable. On physical examination, raised (yellow) papillary lesions, typical of pseudoxanthoma, were found on the neck, axillae, clavicle, thigh, and periumbilical regions. External and anterior segment examinations (of her eyes) were unremarkable. She was found to have a best-corrected visual acuity of 20/10 in both eyes. Intraocular pressure was normal. Funduscopy revealed bilateral angioid streaks, crystalline bodies, and "peau d'orange," but to a lesser extent than in her sister. In both cases, after informed consent, peripheral blood cells were taken and sent for extraction of DNA. Analysis was performed but could not demonstrate the known gene defects of PXE.

Gronblad Strandberg syndrome with vertibrobasilar dolichoectasia

The constellation of pseudoxanthoma elasticum, ocular involvement and vascular disturbances is termed Gronblad Strandberg syndrome. Pseudoxanthoma elasticum is a genetic disorder characterized by progressive calcification and fragmentation of elastic fibres in the skin, retina and the cardiovascular system. Typically the cutaneous lesions begin in childhood, but because of their asymptomatic nature they are not noted until adolescence. In some individuals, skin lesions do not develop until later in life. If recognized early, the occurrence of retinal and gastrointestinal hemorrhage and cardiovascular complications can be minimized.

Pseudoxanthoma elasticum-like papillary dermal elastolysis

Elastolysis refers to a loss of elastic fibers. It can affect the papillary dermis, the reticular dermis, or both. Pseudoxanthoma elasticum-like papillary dermal elastolysis (PXE-PDE) is a clinicopathological entity first described by Rongioletti and Rebora in 1992 (1). It is an acquired elastolytic disorder that mainly affects the papillary dermis. Clinically it resembles pseudoxanthoma elasticum (PXE), but it differs histologically and there is no systemic involvement, in contrast to PXE.

[Pseudoxanthoma elasticum]

During childhood two women developed yellowish xanthoma-like papules on the neck. After dermatological examination and skin biopsy, the diagnosis pseudoxanthoma elasticum (PXE) was made. PXE is a hereditary metabolic disease which has an early onset with characteristic skin lesions. Early diagnosis and follow-up is essential to prevent serious ocular or cardiovascular complications. Follow-up standards are lacking for these patients.

Late-onset focal dermal elastosis: a case report and review of the literature

Late-onset focal dermal elastosis is a condition characterized by a localized increase in healthy-appearing elastic tissue in the mid and deep reticular dermis. The condition may clinically mimic pseudoxanthoma elasticum (PXE) and linear focal elastosis. We report a case of an 87-year-old woman who presented with a markedly thickened, yellow, pruritic plaque on the posterior neck and discuss the clinical and histopathologic distinctions between late-onset focal dermal elastosis, PXE, and linear focal elastosis.

[Pseudoxanthoma elasticum beyond skin, eyes and vessels]

The main clinical manifestations of pseudoxanthoma elasticum (PXE) alter small arteries, the eyes and the skin. At the microanatomical level, the feature in common is an alteration of the elastic fibres that appear dystrophic and in part calcified. The disease is genetically transmitted as an autosomal recessive trait. The gene coding for the MRP6 protein is often mutated. Thus PXE appears as a metabolic disease conveyed by serum.

[Pseudoxanthoma elasticum: a study of 22 cases]

Pseudoxanthoma elasticum is a heritable connective-tissue disorder affecting the eye, skin, and vascular system. The aim of our study was to specify the epidemiological and clinical characteristics of this disease in a hospital series. A total of 22 patients were included during a period of 19 years. There were 15 women and 7 men. Patient's mean age was of 36,1 years. Parental inbreeding was reported in 10 cases. However, the parents were apparently healty. All patients exhibited cutaneous signs. The association between pseudoxanthoma elasticum and elastosis perforans serpiginosa was reported in two cases. The histological features were characteristic in all cases. The ophthalmologic examination realized on 13 patients revealed angioid streaks in 6 cases and a orange peel aspect in one case. Cardiac evaluation performed in 11 patients did not reveal specific PXE abnormalities. A follow-up was recommended in the majority of the cases. In conclusion, a family history of PXE was frequently reported in our study mainly among brothers and sisters. The disease was probably of autosomal recessive transmission. Cutaneous lesions were often the first signs. A list of laboratory investigations is useful to search for asymptomatic visceral localizations and specify their frequency.

Pseudoxanthoma elasticum: clinical phenotypes, molecular genetics and putative pathomechanisms

Pseudoxanthoma elasticum (PXE), a prototype of heritable multisystem disorders, is characterised by pathologic mineralisation of connective tissues, with primary clinical manifestations in the skin, eyes and the cardiovascular system. The causative gene was initially identified as ABCC6 which encodes an ABC transporter protein (ABCC6) expressed primarily in the liver and the kidneys. The critical role of ABCC6 in ectopic mineralisation has been confirmed by the development of Abcc6(-/-) knock-out mice which recapitulate the features of connective tissue mineralisation characteristic of PXE. Over 300 distinct loss-of-function mutations representative of over 1000 mutant alleles in ABCC6 have been identified by streamlined mutation detection strategies in this autosomal recessive disease. More recently, missense mutations in the GGCX gene, either in compound heterozygous state or digenic with a recurrent ABCC6 nonsense mutation (p.R1141X), have been identified in patients with PXE-like cutaneous findings and vitamin K-dependent coagulation factor deficiency. GGCX encodes a carboxylase which catalyses gamma-glutamyl carboxylation of coagulation factors as well as of matrix gla protein (MGP) which in fully carboxylated form serves as a systemic inhibitor of pathologic mineralisation. Collectively, these observations suggest the hypothesis that a consequence of loss-of-function mutations in the ABCC6 gene is the reduced vitamin K-dependent gamma-glutamyl carboxylation of MGP, with subsequent connective tissue mineralisation. Further progress in understanding the detailed pathomechanisms of PXE should provide novel strategies to counteract, and perhaps cure, this complex heritable disorder at the genome-environment interface.