Steatohepatitis and unsuspected micronodular cirrhosis in Dorfman-Chanarin syndrome with documented ABHD5 mutation

ABHD5-A Regulator of Lipid Metabolism Essential for Diverse Cellular Functions

The α/β-Hydrolase domain-containing protein 5 (ABHD5; also known as comparative gene identification-58, or CGI-58) is the causative gene of the Chanarin-Dorfman syndrome (CDS), a disorder mainly characterized by systemic triacylglycerol accumulation and a severe defect in skin barrier function. The clinical phenotype of CDS patients and the characterization of global and tissue-specific ABHD5-deficient mouse strains have demonstrated that ABHD5 is a crucial regulator of lipid and energy homeostasis in various tissues. Although ABHD5 lacks intrinsic hydrolase activity, it functions as a co-activating enzyme of the patatin-like phospholipase domain-containing (PNPLA) protein family that is involved in triacylglycerol and glycerophospholipid, as well as sphingolipid and retinyl ester metabolism. Moreover, ABHD5 interacts with perilipins (PLINs) and fatty acid-binding proteins (FABPs), which are important regulators of lipid homeostasis in adipose and non-adipose tissues. This review focuses on the multifaceted role of ABHD5 in modulating the function of key enzymes in lipid metabolism.

An Adolescent with Chanarin-Dorfman Syndrome Presenting with Ichthyosis and Hepatic Steatosis

Chanarin-Dorfman syndrome also known as neutral lipid storage disease is a rare multisystemic autosomal recessive disorder. It is mostly encountered in patients of Mediterranean and Middle Eastern origin. Most patients are brought to medical attention secondary to dermatological manifestations namely ichthyosis. Here, we report a 10-year-old Kurdish male patient with ichthyosis, who was referred to pediatric liver clinic for transaminase elevation of unknown etiology despite elaborate workup. Histological findings on liver biopsy were consistent with nonalcoholic steatohepatitis. Genetic testing identified homozygous mutation C.776G>A (p.G259D) in the Abhydrolase domain containing 5 gene on chromosome 3 described in patients with Chanarin-Dorfman syndrome. After the initiation of a diet with high medium chain triglycerides/long chain triglycerides ratio, aerobic exercise, and vitamin E, the patient liver enzymes improved. Due to debilitating ichthyosis, he was started on acitretin therapy that was discontinued due to transaminases elevation. Patient is currently stable and doing well.

Dorfman-Chanarin Syndrome: A Rare Cause of Metabolic Associated Fatty Liver Disease Related to Homozygosity of the Nonsense Mutation c.934C>T (p.R312*)

Metabolic associated fatty liver disease became the most common form of chronic liver disease, in the vast majority of the cases related to increased insulin resistance or metabolic dysregulation. Yet, other causes may be implied. We report the late diagnosis of Dorfman-Chanarin syndrome in a non-alcoholic steatohepatitis previously labeled cirrhotic middle-aged man, with consanguineous parents, complicated with hepatocellular carcinoma. Congenital ichthyosis, neurosensory hearing loss and elevated muscular enzymes hit on the track of Dorfman-Chanarin syndrome. The genetic analysis uncovered a first-time described homozygotic nonsense mutation in the ABHD5 gene, responsible for coding the ABHD5 protein. The patient was successfully submitted to liver transplantation. Inborn errors of metabolism are a rare cause of metabolic associated fatty liver disease, but they need to be kept in consideration in all patients who present with atypical clinical features. This shall raise the awareness of physicians to rare forms of presentation since it may imply not only a different prognosis, but also other actions, like particular therapies as liver transplantation due to related complications of cirrhosis, or familial screening.

Chanarin-Dorfman Syndrome: A comprehensive review

The Chanarin-Dorfman syndrome (CDS) is a rare, autosomal recessively inherited genetic disease. This syndrome is associated with a decrease in the lipolysis activity in multiple tissue cells because of recessive mutations in the abhydrolase domain containing 5 (ABHD5) gene, which leads to the accumulation of lipid droplets in multiple types of cells. Major clinical symptoms in patients with CDS include ichthyosis and intracytoplasmic lipid droplets. The variability of clinical symptoms in patients with CDS depends on a large number of mutations involved. In this syndrome, liver involvement is an important cause of mortality and morbidity. This review aims to summarize the demographic characteristic, clinical symptoms, liver involvement and mutations in CDS patients in the literature to date.

CGI-58: Versatile Regulator of Intracellular Lipid Droplet Homeostasis

Comparative gene identification-58 (CGI-58), also known as α/β-hydrolase domain-containing 5 (ABHD5), is a member of a large family of proteins containing an α/β-hydrolase-fold. CGI-58 is well-known as the co-activator of adipose triglyceride lipase (ATGL), which is a key enzyme initiating cytosolic lipid droplet lipolysis. Mutations in either the human CGI-58 or ATGL gene cause an autosomal recessive neutral lipid storage disease, characterized by the excessive accumulation of triglyceride (TAG)-rich lipid droplets in the cytoplasm of almost all cell types. CGI-58, however, has ATGL-independent functions. Distinct phenotypes associated with CGI-58 deficiency commonly include ichthyosis (scaly dry skin), nonalcoholic steatohepatitis, and hepatic fibrosis. Through regulated interactions with multiple protein families, CGI-58 controls many metabolic and signaling pathways, such as lipid and glucose metabolism, energy balance, insulin signaling, inflammatory responses, and thermogenesis. Recent studies have shown that CGI-58 regulates the pathogenesis of common metabolic diseases in a tissue-specific manner. Future studies are needed to molecularly define ATGL-independent functions of CGI-58, including the newly identified serine protease activity of CGI-58. Elucidation of these versatile functions of CGI-58 may uncover fundamental cellular processes governing lipid and energy homeostasis, which may help develop novel approaches that counter against obesity and its associated metabolic sequelae.

Thyroid involvement in Chanarin-Dorfman syndrome in adults in the largest series of patients carrying the same founder mutation in ABHD5 gene

Background

Chanarin-Dorfman syndrome (CDS) is a rare syndromic disease related to an accumulation of triacylglycerol in most organs. The aim of our study was to investigate various organs in a large series of CDS patients.

Results

We report for the first time thyroid function impairment in CDS. Among 12 investigated patients, 7 showed thyroid function impairment. All of them were over 30 of age. The 5 remaining investigated patients with normal thyroid function were under 30. Thyroid loss of function is an unknown clinical feature of CDS that could gradually develop with age. Thyroid ultrasound showed an abnormal aspect in all investigated patients (6 with thyroid impairment and 3 with normal thyroid function). Cervical MRI done in 2 patients with thyroid impairment showed fat infiltration of thyroid parenchyma. Audiogram carried out in 8 of our patients showed sensorineural hearing impairment in all patients, although only 2 patients suffered from clinical hypoacusia. We also demonstrated that kidney could be a more commonly involved organ than previously reported in the literature. A poorly differentiated kidney parenchyma is a common feature in our series. One patient showed cerebellar atrophy and T2 hypersignal of brain’s white matter in MRI. All patients carried the same founder mutation c.773(− 1)G > A in the ABDH5 gene.

Discussion

Aside from the congenital ichthyosiform erythroderma, the most common symptom of CDS, in addition to other organs involvement frequently reported in the literature, we described thyroid dysfunction, an unreported feature, probably related to the lipid infiltration of the thyroid parenchyma. The association found between age and hypothyroidism in CDS patients could explain the gradually development of thyroid disease with age.

Conclusion

We reported a thyroid dysfunction and unreported ultrasonographic aspects of kidneys and cerebral MRI in CDS patients.

Methods

We performed clinical analyses in 15 patients in whom thyroid, liver, ocular, kidney, skeletal muscle and neurological involvement were explored. Genetic and molecular explorations were performed by direct sequence analysis. Software SPSS, Fisher’s exact test and ANOVA were used for statistical analyses.

Electronic supplementary material

The online version of this article (10.1186/s13023-019-1095-4) contains supplementary material, which is available to authorized users.

Critical roles for α/β hydrolase domain 5 (ABHD5)/comparative gene identification-58 (CGI-58) at the lipid droplet interface and beyond

Mutations in the gene encoding comparative gene identification 58 (CGI-58), also known as α β hydrolase domain-containing 5 (ABHD5), cause neutral lipid storage disorder with ichthyosis (NLSDI). This inborn error in metabolism is characterized by ectopic accumulation of triacylglycerols (TAG) within cytoplasmic lipid droplets in multiple cell types. Studies over the past decade have clearly demonstrated that CGI-58 is a potent regulator of TAG hydrolysis in the disease-relevant cell types. However, despite the reproducible genetic link between CGI-58 mutations and TAG storage, the molecular mechanisms by which CGI-58 regulates TAG hydrolysis are still incompletely understood. It is clear that CGI-58 can regulate TAG hydrolysis by activating the major TAG hydrolase adipose triglyceride lipase (ATGL), yet CGI-58 can also regulate lipid metabolism via mechanisms that do not involve ATGL. This review highlights recent progress made in defining the physiologic and biochemical function of CGI-58, and its broader role in energy homeostasis. This article is part of a Special Issue entitled: Recent Advances in Lipid Droplet Biology edited by Rosalind Coleman and Matthijs Hesselink.

Omic studies reveal the pathogenic lipid droplet proteins in non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is an epidemic metabolic condition driven by an underlying lipid homeostasis disorder. The lipid droplet (LD), the main organelle involved in neutral lipid storage and hydrolysis, is a potential target for NAFLD therapeutic treatment. In this review, we summarize recent progress elucidating the connections between LD-associated proteins and NAFLD found by genome-wide association studies (GWAS), genomic and proteomic studies. Finally, we discuss a possible mechanism by which the protein 17β-hydroxysteroid dehydrogenase 13 (17β-HSD13) may promote the development of NAFLD.

Deficiency of liver Comparative Gene Identification-58 causes steatohepatitis and fibrosis in mice

Triglyceride (TG) accumulation in hepatocytes (hepatic steatosis) preludes the development of advanced nonalcoholic fatty liver diseases (NAFLDs) such as steatohepatitis, fibrosis, and cirrhosis. Mutations in human Comparative Gene Identification-58 (CGI-58) cause cytosolic TG-rich lipid droplets to accumulate in almost all cell types including hepatocytes. However, it is unclear if CGI-58 mutation causes hepatic steatosis locally or via altering lipid metabolism in other tissues. To directly address this question, we created liver-specific CGI-58 knockout (LivKO) mice. LivKO mice on standard chow diet displayed microvesicular and macrovesicular panlobular steatosis, and progressed to advanced NAFLD stages over time, including lobular inflammation and centrilobular fibrosis. Compared with CGI-58 floxed control littermates, LivKO mice showed 8-fold and 52-fold increases in hepatic TG content, which was associated with 40% and 58% decreases in hepatic TG hydrolase activity at 16 and 42 weeks, respectively. Hepatic cholesterol also increased significantly in LivKO mice. At 42 weeks, LivKO mice showed increased hepatic oxidative stress, plasma aminotransferases, and hepatic mRNAs for genes involved in fibrosis and inflammation, such as α-smooth muscle actin, collagen type 1 α1, tumor necrosis factor α, and interleukin-1β. In conclusion, CGI-58 deficiency in the liver directly causes not only hepatic steatosis but also steatohepatitis and fibrosis.

The G0/G1 switch gene 2 (G0S2): regulating metabolism and beyond

The G0/G1 switch gene 2 (G0S2) was originally identified in blood mononuclear cells following induced cell cycle progression. Translation of G0S2 results in a small basic protein of 103 amino acids in size. It was initially believed that G0S2 mediates re-entry of cells from the G0 to G1 phase of the cell cycle. Recent studies have begun to reveal the functional aspects of G0S2 and its protein product in various cellular settings. To date the best-known function of G0S2 is its direct inhibitory capacity on the rate-limiting lipolytic enzyme adipose triglyceride lipase (ATGL). Other studies have illustrated key features of G0S2 including sub-cellular localization, expression profiles and regulation, and possible functions in cellular proliferation and differentiation. In this review we present the current knowledge base regarding all facets of G0S2, and pose a variety of questions and hypotheses pertaining to future research directions.

Steatohepatitis and liver cirrhosis in Chanarin-Dorfman syndrome with a new ABDH5 mutation

Chanarin-Dorfman syndrome (CDS) is an autosomal recessive neutral lipid storage disease. It is very rare and characterized by ichtiosis, intracellular fat droplets in leucocytes (Jordan anomaly) and involvement of multiple tissues (skeletal muscle, central nervous system, bone marrow, eye and ear) mainly the liver. Our patients were diagnosed as CDS because they had ichtiosis, Jordon anomaly of leucocytes in peripheral blood smear, liver involvement and presence of homozygous 88 insertion C frame shift mutation on exon 4 of ABHD5/CGI-58 gene in genetic analysis. Our cases were two sisters. One of them developed severe steatohepatitis on age 19 and the other one was diagnosed as decompensated cirrhosis when she was 26 years old. We report here a new mutation in comparative gene identification-58 (CGI-58) gene causing syndactyly and steatohepatitis induced early cirrhosis.

Fat in the skin: Triacylglycerol metabolism in keratinocytes and its role in the development of neutral lipid storage disease

Keratinocyte differentiation is essential for skin development and the formation of the skin permeability barrier. This process involves an orchestrated remodeling of lipids. The cleavage of precursor lipids from lamellar bodies by β-glucocerebrosidase, sphingomyelinase, phospholipases and sterol sulfatase generates ceramides, non-esterified fatty acids and cholesterol for the lipid-containing extracellular matrix, the lamellar membranes in the stratum corneum. The importance of triacylglycerol (TAG) hydrolysis for the formation of a functional permeability barrier was only recently appreciated. Mice with defects in TAG synthesis (acyl-CoA:diacylglycerol acyltransferase-2-knock-out) or TAG catabolism (comparative gene identification-58, -CGI-58-knock-out) develop severe permeability barrier defects and die soon after birth because of desiccation. In humans, mutations in the CGI-58 gene also cause (non-lethal) neutral lipid storage disease with ichthyosis. As a result of defective TAG synthesis or catabolism, humans and mice lack ω-(O)-acylceramides, which are essential lipid precursors for the formation of the corneocyte lipid envelope. This structure plays an important role in linking the lipid-enriched lamellar membranes to highly cross-linked corneocyte proteins. This review focuses on the current knowledge of biochemical mechanisms that are essential for epidermal neutral lipid metabolism and the formation of a functional skin permeability barrier.

A rare cause of Fatty liver and elevated aminotransferase levels: chanarin-dorfman syndrome: a case report

Chanarin-Dorfman syndrome is a rare, inherited metabolic disorder of neutral lipid storage characterized by ichthyosis, lipid vacuoles in leukocytes, and involvement of several internal organs, mostly the liver. Since the initial case was reported by Dorfman in 1974, nearly 50 cases have been reported, and the majority were from Middle East countries. Here, we report a 20-year-old patient with ichthyosis from Turkey, diagnosed as Chanarin-Dorfman syndrome presented with asypmtomatic elevated transaminases and hepatosteatosis, and also briefly review the updated clinical implications and management of this rarely seen syndrome. Prompt diagnosis of this syndrome avoids further unnecessary investigations in patients with ichthyosis.

Molecular analysis of Chanarin-Dorfman syndrome (CDS) patients: Identification of novel mutations in the ABHD5 gene

Chanarin-Dorfman syndrome (CDS) is an autosomal recessive metabolic disorder associated with congenital ichthyosis and a multisystemic accumulation of neutral lipids in various types of cells. Recently, mutations of the ABHD5 gene were identified as the cause of CDS. In this work, we carried out molecular analysis of the ABHD5 gene in 6 unrelated patients. We identified one previously reported mutation, N209X and two novel genetic alterations; a nonsense mutation (p.Y50X) and missense mutation (p.S73A).

Neutral lipid storage disease: genetic disorders caused by mutations in adipose triglyceride lipase/PNPLA2 or CGI-58/ABHD5

Neutral lipid storage disease (NLSD) is a group of autosomal recessive disorders characterized by the excessive accumulation of neutral lipids in multiple tissues. Recently, two genes, adipose triglyceride lipase (ATGL/PNPLA2) and comparative gene identification-58 (CGI-58/ABHD5), have been shown to cause NLSD. ATGL specifically hydrolyzes the first fatty acid from triacylglycerols (TG) and CGI-58/ABHD5 stimulates ATGL activity by a currently unknown mechanism. Mutations in both the ATGL and the CGI-58 genes are associated with systemic TG accumulation, yet the resulting clinical manifestations are not identical. Patients with defective ATGL function suffer from more severe myopathy (NLSDM) than patients with defective CGI-58 function. On the other hand, CGI-58 mutations are always associated with ichthyosis (NLSDI), which was not observed in patients with defective ATGL function. These observations indicate an ATGL-independent function of CGI-58. This review summarizes recent findings with the goal of relating structural variants of ATGL and CGI-58 to functional consequences in lipid metabolism.

Severe steatohepatitis in a patient with a rare neutral lipid storage disorder due to ABHD5 mutation

Fatty liver disease is mainly caused by alcohol consumption, excessive body weight, dyslipidemia and impaired glucose tolerance, but inherited disorders can sometimes be involved. We report the case of a 40-year-old woman with steatohepatitis and severe portal hypertension, associated with ichthyosis, cataract and hypoacusia. The clinical, pathological and genetic findings were consistent with a diagnosis of Chanarin-Dorfman syndrome (CDS), a rare autosomal recessive inherited neutral lipid storage disorder, and genetic analysis showed that a novel ABHD5 mutation is responsible.

Renal involvement as a rare complication of Dorfman-Chanarin syndrome: a case report

Dorfman-Chanarin syndrome is a rare, autosomal recessive inherited lipid storage disease with congenital ichthyotic erythroderma due to an acylglycerol recycling defect. It is characterized by accumulation of neutral lipids in different tissues. Liver, muscle, ear, eye, and central nervous system are generally involved, so we presented a patient with severe ichthyosis, lipid vacuoles in neutrophils, and multiorgan involvement including a very rare complication, renal involvement. A 7-month-old girl was presented with frequent respiratory infection, congenital ichthyotic erithroderma and suspicion for immune deficiency. On her physical examination hepatomegaly, developmental delay, palmar and plantar hyperkeratosis and increased deep tendon reflexes with clonus and high tonus were found. Laboratory investigations revealed elevation at transaminases levels, hypoalbuminemia, hypergammaglobulinemia, presence of autoantibodies and eosinophilia. Vacuolization in leukocytes confirmed Dorfman-Chanarin syndrome, whereas no mutation at RAG1-2 and ARTEMIS genes ruled-out immune deficient status of the patient. At the age of eight months the patient died from severe renal failure. Her necropsies demonstrated microvesicular lipid accumulation not only at the liver but also at the renal species. The variability of involvement of different systems in Dorfman-Chanarin syndrome is well described, however the renal findings has not been reported previously at the literature.

Clinical and genetic characterization of Chanarin-Dorfman syndrome

We describe the clinical features, muscle pathology features, and molecular studies of seven patients with Chanarin-Dorfman syndrome (CDS) or neutral lipid storage disease and ichthyosis (NLSDI), a multisystem triglyceride storage disease with massive accumulation of lipid droplets in muscle fibers. All patients presented with congenital ichthyosiform erythroderma, cytoplasmic lipid droplets in blood cells, mild to severe hepatomegaly, and increased serum CK levels and liver enzymes. Three patients showed muscle symptoms and three had steathorrea. Molecular analysis identified five mutations, three of which are novel. These findings expand the clinical and mutational spectrum and underline the genetic heterogeneity of this disease.

CGI-58 facilitates the mobilization of cytoplasmic triglyceride for lipoprotein secretion in hepatoma cells

Comparative Gene Identification-58 (CGI-58) is a member of the alpha/beta-hydrolase family of proteins. Mutations in the human CGI-58 gene are associated with Chanarin-Dorfman syndrome, a rare autosomal recessive genetic disease in which excessive triglyceride (TG) accumulation occurs in multiple tissues. In this study, we investigated the role of CGI-58 in cellular lipid metabolism in several cell models and discovered a role for CGI-58 in promoting the packaging of cytoplasmic TG into secreted lipoprotein particles in hepatoma cells. Using both gain-of-function and loss-of-function approaches, we demonstrate that CGI-58 facilitates the depletion of cellular TG stores without altering cellular cholesterol or phospholipid accumulation. This depletion of cellular TG is attributable solely to augmented hydrolysis, whereas TG synthesis was not affected by CGI-58. Furthermore, CGI-58-mediated TG hydrolysis can be completely inhibited by the known lipase inhibitors diethylumbelliferyl phosphate and diethyl-p-nitrophenyl phosphate, but not by p-chloro-mercuribenzoate. Intriguingly, CGI-58-driven TG hydrolysis was coupled to increases in both fatty acid oxidation and secretion of TG. Collectively, this study reveals a role for CGI-58 in coupling lipolytic degradation of cytoplasmic TG to oxidation and packaging into TG-rich lipoproteins for secretion in hepatoma cells.

Pediatric nonalcoholic fatty liver disease (NAFLD): a "growing" problem?

Nonalcoholic fatty liver disease (NAFLD) can affect both adults and children. With the current worldwide epidemic of pediatric obesity, pediatric NAFLD is increasingly being diagnosed. It is not exactly identical to NAFLD in adults, and these differences may be due in part to the occurrence of hepatic metabolic derangements typical of NAFLD during periods of active growth (infancy, mid-childhood and puberty). The natural history of pediatric NAFLD is not yet known; however, children with pediatric NAFLD can develop cirrhosis. Although details of disease mechanism in pediatric NAFLD remain unclear, hyperinsulinemia with insulin resistance appears to be critical. Determining the pathogenesis of pediatric NAFLD is likely to enhance our understanding of NAFLD in all age groups and may identify new treatment opportunities. Finding effective ways to prevent pediatric NAFLD is an important issue for children's health.

A case with full clinical manifestations of Dorfman-Chanarin syndrome

Dorfman-Chanarin syndrome (DCS), is a rare, autosomal recessive disorder associated with lipid metabolism. It is characterized by ichthyosiform nonbullous erythroderma, lipid vacuoles in peripheral leukocytes and variable involvement of organs. We report a Turkish man with the complete syndrome, who described family history of ichthyosis. To best of our knowledge this is the sixth case from Turkish origin to date. In addition to congenital ichthyosis he had also strabismus, horizantal nystagmus, bilateral neurosensory hearing loss, hepatomegaly and splenomegaly. Liver biopsy revealed hidrophic degeneration in hepatocytes, steatosis, enlargement and inflammation in portal areas and portal central fibrosis, consistent with cirrhosis. Write stained peripheral blood smear examination revealed lipid vacuoles in all of the neutrophils consistent with Jordan’s anomaly. We think that, it is essential to evaluate the peripheral blood smear of the patients with ichthyosis and also patients with DCS should be informed and warned about the results of consanquinous marriage.

Non-alcoholic steatohepatitis in children

Non-alcoholic steatohepatitis (NASH) is an important liver disease in children; it can cause cirrhosis in children. The disease mechanism involves hepatic insulin resistance with hyperinsulinemia and changes in certain adipocytokines and inflammatory mediators. The differential diagnosis of childhood NASH includes metabolic disorders, drug hepatotoxicity, and alcoholic hepatitis in adolescent patients. The histologic features in childhood NASH often differ from those in adults who have NASH. Treatment is gradual weight loss through changes in food intake patterns and increased levels of physical activity; the role of drug treatment of NASH in children is an area of ongoing research.

Rickets with Dorfman-Chanarin syndrome

BACKGROUND

Dorfman-Chanarin syndrome is a rare, autosomal recessive, inherited, lipid storage disease. It is characterized by nonbullous congenital ichthyosiform erythroderma, leukocyte vacuoles and variable involvement of the liver, muscles and central nervous system, due to errors of triacylglycerol metabolism. To date only 32 cases of this syndrome have been described worldwide.

AIMS

To report the case of a boy with Dorfman-Chanarin syndrome with rickets.

CASE REPORT

A boy of Turkish origin was born of a nonconsanguineous marriage after an uncomplicated perinatal period. On examination the patient had failure to thrive, diffuse erythroderma and ichthyosis and clinical features suggesting rickets. A light-microscopic examination of peripheral smear revealed vacuolated leukocytes typical of Jordans' anomaly. Lipid analysis showed an increase in triacylglycerol and very low density lipoprotein. A radiographic study of the wrist revealed rickets.

CONCLUSION

The clinical progression in these patients ranges from mild to fatal. We believe that patients with ichthyosis should be evaluated bearing in mind the possibility of Dorfman-Chanarin syndrome. This may increase the number of reported Dorfman-Chanarin syndrome cases, and the pathogenesis and progression of the disease will become clearer.

VPS33B mutation with ichthyosis, cholestasis, and renal dysfunction but without arthrogryposis: incomplete ARC syndrome phenotype

Arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome is a rare multisystem disorder first described in 1979 and recently ascribed to mutation in VPS33B, whose product acts in intracellular trafficking. Arthrogryposis, spillage of various substances in the urine, and conjugated hyperbilirubinemia define an ARC core phenotype, in some patients associated with ichthyosis, central nervous system malformation, deafness, and platelet abnormalities. We describe a patient with cholestasis, aminoaciduria, ichthyosis, partial callosal agenesis, and sensorineural deafness who, although homozygous for the novel VPS33B mutation 971delA/K324fs, predicted to abolish VPS33B function, did not exhibit arthrogryposis. The phenotypes associated with VPS33B mutation may include incomplete ARC.

Nonalcoholic fatty liver disease in children

Nonalcoholic fatty liver disease (NAFLD) is likely to reach epidemic proportions in children worldwide in the next decade. NAFLD may be the hepatic aspect of the metabolic syndrome in adults and children. The entire range of liver involvement characterizing NAFLD can occur in children: hepatic macrovesicular steatosis without inflammation, steatosis with inflammation or fibrosis, and cirrhosis. NAFLD may be more severe in children from certain ethnic groups or in association with metabolic disorders characterized by abnormalities in insulin receptor structure and function. Treatment strategies focus on modifying risk factors because specific drug treatments are lacking. Overweight/obesity should be identified as early as possible. Comprehensive clinical management to normalize weight should be instituted immediately to avoid hepatic and nonhepatic complications.

Erythrokeratoderma variabilis-like ichthyosis in Chanarin-Dorfman syndrome

Neutral lipid storage disease (Chanarin-Dorfman syndrome) is an autosomal recessive metabolic disorder associated with congenital ichthyosis and a multisystemic accumulation of neutral lipids (lipid droplets) in various types of cells. The clinical presentation has been reported to correspond to that of nonbullous congenital ichthyosiform erythroderma. We report a 4-year-old boy presenting a generalized ichthyosiform disorder manifested by migrating scaly plaques alternating with areas of normal-looking skin, showing erythematous borders with sharp margins, clinically suggestive of erythrokeratoderma variabilis (EKV). A peripheral blood smear revealed cytoplasmic vacuoles in most granulocytes. Genetic studies from the patient and his parents revealed that the patient carried two different and novel mutations of the ABHD5 gene: a nonsense mutation in exon 6 (transmitted by the father) and an insertion/deletion in exon 4 (transmitted by the mother). Our observation demonstrates the clinical heterogeneity of the ichthyosiform dermatoses observed in Chanarin-Dorfman syndrome and widens the clinical range of conditions presenting migrating scaly plaques mimicking EKV.