The histopathology and phenotypic variability in H syndrome.

Skin biopsy may be helpful in the diagnosis of H syndrome. A triad of dermal fibrosis, lymphocytic aggregates, and numerous CD68+, CD163+, S100-positive, and CD1a-negative dermal histiocytes is characteristic.

Clinico-pathological manifestations of variant late infantile neuronal ceroid lipofuscinosis (vLINCL) caused by a novel mutation in MFSD8 gene.

Neuronal ceroid lipofuscinosis (NCL) refers to a growing heterogeneous group of neurodegenerative disorders characterized by lysosomal accumulation of abnormal autofluorescent material. NCLs are traditionally classified clinically according to their age of onset. Variable late infantile NCL (vLINCL) is the most genetically heterogeneous subtype as it has been shown to be caused by mutations in at least six genes. We report on 5 patients of a consanguineous family who presented in early childhood with intractable seizures, severe cognitive and motor decline, behavioral impairment and progressive retinal degeneration. Disease course was severe; all patients were in a vegetative state by the second decade of life, and eventually die prematurely (except in one case). Ultrastructural studies of brain and rectal mucosa disclosed accumulation of storage material in various patterns including fingerprint, curvilinear, and granular osmiophilic deposits consistent with the diagnosis of NCL. Brain pathologic features from a living patient are first reported here and shed light on disease progression and pathogenesis. Using a combination of whole genome autozygosity mapping and candidate gene direct sequencing, we identified a mutation in MFSD8, c.472G>A (p.Gly158Ser), which was found to segregate with the disease phenotype in the family. This study underscores the importance of a combined clinic-molecular workup in NCLs and other neurodegenerative conditions.

Human amnion membrane as a substrate for the detection of autoantibodies in pemphigus vulgaris and bullous pemphigoid.

BACKGROUND: Human amnion membrane (HAM) was suggested to be a superior antigenic substrate for immunoblotting in detecting autoantibodies of autoimmune bullous skin diseases. OBJECTIVES: To determine the properties of HAM as an antigenic substrate for the detection of autoantibodies in pemphigus vulgaris and bullous pemphigoid. METHODS: Immunomapping and tandem liquid chromatography mass spectrometry were used to delineate the antigenic structure of HAM. Immunoblotting and indirect immunofluorescence were used to study the diagnostic utility of HAM in 25 pemphigus patients, 41 pemphigoid patients, and 36 controls, and the results were compared to those of indirect immunofluorescence on monkey esophagus, immunoblotting using normal human skin, and enzyme-linked immunosorbent assay. RESULTS: Immunomapping demonstrated the presence of all the antigens known to be targeted in autoimmune bullous skin diseases, in both normal human skin and HAM, except for the absence of BP230, and low threshold levels of Dsg1, Dsg3 and Dsc3 in HAM. HAM indirect immunofluorescence demonstrated anti-basement membrane zone antibodies in 48.7% of the pemphigoid patients, and anti-intercellular space antibodies in 72.0% of the pemphigus patients. HAM immunoblotting did not demonstrate anti-BP230 antibodies, but detected anti-BP180 antibodies in 53.7% of the pemphigoid patients. It did not demonstrate anti-Dsg1 and/ or anti-Dsg3 antibodies in any of the pemphigus patients. These results were inferior to those of ELISA and monkey esophagus indirect immunofluorescence. CONCLUSIONS: Compared to other studied methods, HAM does not offer advantages in detecting autoantibodies in bullous pemphigoid and pemphigus vulgaris.

Molecular analysis of a series of Israeli families with Comèl-Netherton syndrome.

BACKGROUND: Comèl-Netherton syndrome is a rare congenital autosomal recessive disorder characterized by congenital ichthyosis, hair shaft abnormalities and atopic diathesis. It is caused by mutations in SPINK5, which encodes the serine protease inhibitor LEKTI. OBJECTIVES: To delineate the spectrum of mutations carried by a series of Israeli patients in an attempt to establish an effective diagnostic strategy for this disease in Israel. METHODS: Mutations were identified by direct sequencing of the entire coding sequence of SPINK5 and confirmed using polymerase chain reaction-restriction fragment length polymorphism. RESULTS: Three mutations were identified in seven families, of which two were novel. All mutations were predicted to result in premature termination of protein translation. CONCLUSIONS: This report presents the first case series of patients affected with Comèl-Netherton syndrome in Israel and suggests that some mutations reoccur in a substantial portion of cases in our country, a fact that should be taken into consideration when designing molecular analysis in new cases.

Postzygotic HRAS mutation causing both keratinocytic epidermal nevus and thymoma and associated with bone dysplasia and hypophosphatemia due to elevated FGF23.

INTRODUCTION: Epidermal nevus syndrome is a rare group of disorders characterized by the combination of congenital epidermal nevi and extracutaneous features, including skeletal, neurological, ocular, and other systemic findings. We report a case of keratinocytic epidermal nevus syndrome that includes a thymoma, bone dysplasia, and hypophosphatemia with elevated fibroblast growth factor 23 (FGF23) levels associated with postzygotic HRAS mutation. CASE REPORT: A 14-year-old boy was admitted due to recent limping. The physical examination revealed multiple right-sided linear epidermal nevi along Blaschko's lines. Magnetic resonance imaging showed cystic lesions in cervical bones and thymoma, and x-ray examination showed cystic lesions in the hands. Biochemical studies demonstrated severe hypophosphatemia, normocalcemia, high normal PTH, low 25-hydroxyvitamin D and low 1,25-dihydroxyvitamin D levels. The serum FGF23 C-terminal level was normal, but the intact FGF23 level was found to be elevated. Genetic evaluation revealed a heterozygote mutation in the HRAS gene in both the keratinocytic epidermal nevus and thymoma but not in DNA extracted from blood lymphocytes, thus establishing the mutation as postzygotic. DISCUSSION: Postzygotic mutations in HRAS lead to elevation of FGF23 levels, as found in mutated PHEX, FGF23, DMP1, and ENPP1 genes, which lead to hypophosphatemia. CONCLUSION: An identical postzygotic HRAS mutation was shown to be present in both keratinocytic epidermal nevus and thymoma and to be associated with bone lesions and hypophosphatemia due to elevated FGF23 levels. These may all be related to the HRAS mutation.

The sound of silence: autosomal recessive congenital ichthyosis caused by a synonymous mutation in ABCA12.

Autosomal recessive congenital ichthyosis refers to a heterogeneous group of cornification disorders of major impact on patients' life. The disease has been linked so far to mutations in 8 distinct genes. We report a consanguineous family of Arab Muslim origin with several members displaying a severe form of congenital ichthyosiform erythroderma. Using a panel of polymorphic microsatellite markers, we identified a region of homozygosity shared by all patients on 2q34, in a region harbouring the ABCA12 gene. Direct sequencing of genomic DNA derived from a patient failed to reveal any obviously pathogenic change in the coding sequence of this gene. In contrast, cDNA sequence analysis revealed the existence of a 163-bp-long deletion in exon 24, thus pointing to a splicing defect. Careful reanalysis of the genomic DNA sequence revealed apart from several known single-nucleotide polymorphisms, a hitherto unreported homozygous synonymous mutation in exon 24 (c.3456G>A; p.S1152S), which was found to lead to the formation of a novel splicing acceptor site. Synonymous mutations have been shown to uncommonly cause inherited disorders in humans. Here, we present the first example of a congenital form of ichthyosis resulting from such a genetic defect.

Acrokeratosis verruciformis of Hopf showing P602L mutation in ATP2A2 and overlapping histopathological features with Darier disease.

The relationship between acrokeratosis verruciformis (AKV) of Hopf and Darier disease (DD) has been debated for several decades. Both diseases are now thought to result from mutations in the same gene, that is, the ATP2A2 gene encoding the sarco (endo) plasmic reticulum Ca ATPase2 pump (SERCA2), although their histopathological features are different. We sought to detect possible overlapping histopathological features between AKV and DD. Fourteen members of a family affected by AKV were analyzed for the underlying molecular genetic derangement, and 3 cases were studied histopathologically using multiple step sections. A heterozygous P602L mutation in ATP2A2 was identified as the underlying cause in this family. This mutation and a heterozygous A698V were previously described in AKV. Both mutations were not among the 162 mutations in ATP2A2, which were reported to date in DD. The histopathological study demonstrated in several consecutive step sections of 2 of the 3 studied cases, foci of small suprabasal clefts with acantholytic keratinocytes, some of which were mildly dyskeratotic. These focal features were reminiscent of the basic histopathological characteristics of DD. These shared histopathological features of AKV with DD suggest that AKV and DD are allelic disorders with variable expression of the same disease, although identical mutations in ATP2A2 in AKV and DD were not reported to date.

Population-specific association between a polymorphic variant in ST18, encoding a pro-apoptotic molecule, and pemphigus vulgaris.

Pemphigus vulgaris (PV) is a severe autoimmune blistering disease caused by anti-epithelial antibodies, leading to disruption of cell-cell adhesion. Although the disease is exceedingly rare worldwide, it is known to be relatively prevalent in Jewish populations. The low prevalence of the disease represents a significant obstacle to a genome-wide approach to the mapping of susceptibility genes. We reasoned that the study of a genetically homogeneous cohort characterized by a high prevalence of PV may help exposing associated signals while reducing spurious results due to population sub-structure. We performed a genome-wide association study using 300K single-nucleotide polymorphisms (SNPs) in a case-control study of 100 PV patients of Jewish descent and 397 matched control individuals, followed by replication of significantly associated SNPs in three additional cohorts of Jewish, Egyptian, and German origin. In addition to the major histocompatibility complex locus, a genomic segment on 8q11.23 that spans the ST18 gene was also found to be significantly associated with PV. This association was confirmed in the Jewish and Egyptian replication sets but not in the German sample, suggesting that ST18-associated variants may predispose to PV in a population-specific manner. ST18 regulates apoptosis and inflammation, two processes of direct relevance to the pathogenesis of PV. Further supporting the relevance of ST18 to PV, we found this gene to be overexpressed in the skin of PV patients as compared with healthy individuals.

A case of H syndrome showing immunophenotye similarities to Rosai-Dorfman disease.

H syndrome (OMIM 612391) is a recently described autosomal recessive genodermatosis characterized by indurated, hyperpigmented, and hypertrichotic skin and systemic manifestations including hepatosplenomegaly, cardiac anomalies, hearing loss, hypogonadism, low height, hypertriglyceridemia, hallux valgus, and flexion contractures. H syndrome results from mutations in the SLC29A3 gene, which encodes the human equilibrative nucleoside transporter hENT3. The cutaneous histopathology is characterized by a striking mononuclear cell infiltrate in the dermis consisting of CD68+ monocyte-derived cells and CD34+ and factor XIIIa+ dendrocytes. We describe a case of H syndrome in which the infiltrating mononuclear cells were CD68+, CD163+, S-100+, and CD1a-, thus simulating the immunophenotype observed in Rosai-Dorfman disease (RDD). The immunostaining for CD21, fascin, and CD34 were negative, and there were also many factor XIIIa+ dendrocytes interspersed within the dense mononuclear cell infiltrate. Recent findings of biallelic mutations in SLC29A3 in 2 families reported to have familial RDD and in a kindred with Faisalabad histiocytosis (OMIM 602782), which is an autosomal inherited form of histiocytosis with similarities to RDD, may explain the RDD-like immunophenotype in our H syndrome case.

ADULT syndrome caused by a mutation previously associated with EEC syndrome.

Acro-Dermato-Ungual-Lacrimal-Tooth (ADULT) syndrome is a rare autosomal dominant syndrome characterized by ectrodactyly or syndactyly, excessive freckling and dry skin, dysplastic nails, lacrimal duct atresia, primary hypodontia and early loss of permanent teeth. ADULT syndrome is one of five such syndromes that result from mutations in TP63, encoding the transcription factor p63. Until now, only four families and three individuals with ADULT syndrome have been reported in the English literature. We present a 14-year-old female patient with ADULT syndrome and discuss phenotype-genotype correlations in the p63 syndromes.

Buschke-Ollendorff syndrome in a three-generation family: influence of a novel LEMD3 mutation to tropoelastin expression.

Buschke-Ollendorff syndrome refers to the concomitant occurrence of connective tissue nevi, composed of elastic fibers in most cases, with osteopoikilosis. This autosomal dominant inherited disorder is caused by mutations in the gene LEMD3 on chromosome 12q14, which induces a rather heterogeneous clinical phenotype. Here, we report on the most proximal germline mutation found to date in the LEMD3 gene, p.Val94fs, in a three-generation Swiss family. Quantitative RNA analyses in affected and non-affected skin tissue from the proband demonstrate a comparable nonsense-mediated decay of mutant LEMD3 mRNA in both tissues; however, different levels of tropoelastin expression suggest that additional factors are involved in the development of the cutaneous lesions.

Disadhesion of epidermal keratinocytes: a histologic clue to palmoplantar keratodermas caused by DSG1 mutations.

BACKGROUND: Recent developments in molecular genetics may lead to re-examination of the histopathology of inherited palmoplantar keratodermas (PPKs) based on more precise groupings of the various entities and syndromes. OBJECTIVE: We sought to characterize the histopathological findings in PPKs associated with mutations in DSG1, which encodes desmoglein 1. METHODS: We studied the histopathology of 3 cases of keratosis palmoplantaris striata type I and one case of diffuse PPK, all associated with autosomal-dominant mutations in DSG1. Our cases for comparison included 4 cases with Mal de Meleda PPK associated with autosomal-recessive SLURP1 mutations, one case with pachyonychia congenita type II PPK associated with an autosomal-dominant KRT17 mutation, and one case with focal PPK associated with an autosomal-dominant KRT16 mutation. RESULTS: The distinguishing histopathological features of the 3 keratosis palmoplantaris striata type I cases and the diffuse PPK case associated with DSG1 mutation were: varying degrees of widening of the intercellular spaces and partial disadhesion of keratinocytes in the mid and upper epidermal spinous cell layers, often extending to the granular cell layer. These findings, which are associated with haploinsufficiency of desmoglein 1, were not observed in any of the other 6 PPK cases. Mild perinuclear eosinophilic condensations and cytoplasmic vacuolizations were observed in the spinous cell layer keratinocytes of the pachyonychia congenita type II PPK and the nonspecified focal PPK cases. LIMITATIONS: There were a limited number of patients and control patients with hereditary PPKs. CONCLUSION: Widening of the intercellular spaces and disadhesion of epidermal keratinocytes may serve as a histologic clue to PPKs caused by DSG1 mutations.

Insulin-like growth factor-binding protein 7 regulates keratinocyte proliferation, differentiation and apoptosis.

Insulin-like growth factor (IGF)-binding protein 7 (IGFBP7) belongs to the IGFBP superfamily, which is involved in the regulation of IGF and insulin signaling. Recently, a global gene expression study revealed that IGFBP7 is downregulated in the psoriatic epidermis, with UVB phototherapy restoring its expression to normal. In the present study, we confirmed that IGFBP7 expression is decreased in psoriatic lesions. Given the previous data suggesting a role for IGFBP7 in the control of cancer cell growth, we investigated its involvement in the regulation of keratinocyte (KC) proliferation and differentiation, which are abnormal in psoriasis. To model IGFBP7 downregulation in vitro, we used IGFBP7-specific small interfering RNA or small hairpin RNA-expressing lentiviral vectors in HaCaT cells or primary human KCs. Downregulation of IGFBP7 was found to markedly enhance KC proliferation in both systems, was associated with a significant decrease in KC susceptibility to tumor necrosis factor-alpha-induced apoptosis, but did not affect senescence. Downregulation of IGFBP7 was also shown to block expression of genes associated with calcium-induced differentiation of human KCs. Finally, recombinant IGFBP7 was found to inhibit KC proliferation and enhanced their apoptosis. These data position IGFBP7 as a regulator of KC proliferation and differentiation, suggesting a potential role for this protein in the pathophysiology and treatment of hyperproliferative dermatoses such as psoriasis.

Newly discovered mutations in the GALNT3 gene causing autosomal recessive hyperostosis-hyperphosphatemia syndrome.

BACKGROUND AND PURPOSE: Periosteal new bone formation and cortical hyperostosis often suggest an initial diagnosis of bone malignancy or osteomyelitis. In the present study, we investigated the cause of persistent bone hyperostosis in the offspring of two consanguineous parents. METHODS: Clinical assessment, imaging, and direct sequencing were used to elucidate the etiology of the condition seen in the patient. RESULTS: Radiological examination revealed periosteal reaction, diaphysitis, and cortical hyperostosis, suggesting osteomyelitis or a bone neoplasm. The clinical and radiological features were also reminiscent of hyperostosis with hyperphosphatemia (HHS), a rare autosomal recessive disease manifesting with recurrent, transient, and painful swelling of the long bones. The identification of two novel heterozygous pathogenic mutations in the GALNT3 gene confirmed a diagnosis of HHS. INTERPRETATION: Molecular analysis represents an invaluable tool in the differential diagnosis of persistent cortical hyperostosis.

A large duplication in LIPH underlies autosomal recessive hypotrichosis simplex in four Middle Eastern families.

Autosomal recessive hypotrichosis simplex (ARHS) manifests with paucity of hair appearing during early childhood. We assessed four affected families. We initially genotyped three of these families for a panel of microsatellite markers spanning all ARHS-associated loci and obtained data suggesting linkage to 3q27, encompassing LIPH, which had previously been shown to be associated with ARHS. Accordingly, a homozygous duplication mutation in exon 2 of this gene (c.280_369dup; p.Gly94_Lys123dup) was found to segregate with the disease in all the families. Through the identification of the first duplication mutation in the human LIPH gene, we provide further evidence supporting a role for the phospholipase signalling pathway in hair growth and differentiation.