Bi-allelic nonsense mutations inABHD5 underlie a mild phenotype of Dorfman-Chanarin syndrome

Case Report: Chanarin-Dorfman Syndrome: A Novel Homozygous Mutation in ABHD5 Gene in a Chinese Case and Genotype-Phenotype Correlation Analysis

The Chanarin-Dorfman syndrome (CDS) is a rare, autosomal recessively inherited genetic disease, whch is associated with a decrease in the lipolysis activity in multiple tissue cells. The clinical phenotype involves multiple organs and systems, including liver, eyes, ears, skeletal muscle and central nervous system. Mutations in ABHD5/CGI58 gene have been confirmed to be associated with CDS. We performed whole exome sequencing on a Chinese CDS patient with skin ichthyosis features mimicking lamellar ichthyosis, ectropion, sensorineural hearing loss, and lipid storage in peripheral blood neutrophils. A novel homozygous missense mutation (p.L154R) in ABHD5 gene was detected in this patient. Genotype-phenotype analysis in reported CDS patients revealed no particular correlation. Our findings further enrich the reservoir of ABHD5 mutations in CDS.

Chanarin–Dorfman syndrome: clinical/genetic features and natural history in six Pakistani patients

Background

Chanarin–Dorfman syndrome (CDS; OMIM # 275630) is a rare neutral lipid storage disorder caused by mutation in ABHD5 (a/b hydrolase domain containing 5″) a cofactor for adipose triglyceride lipase (ATGL) resulting in intracellular accumulation of triacylglycerol (TG) in numerous body tissues. It is an autosomal recessive disorder mutation in ABHD5 that causes the partial or total loss of ATGL activation, leading to the accumulation of TG inside lipid droplets. We aim to assess the clinical and biochemical manifestations, diagnosis, follow-up and genotype–phenotype correlations in six Pakistani pediatric patients with CDS.

Results

Six male patients with mean age 15 months (9–24 months) diagnosed as CDS on the basis of non-bullous ichthyosiform erythroderma, hepatomegaly and Jordans bodies in peripheral smear. We identified two novel mutations in ABHD5 gene (c.338G > T and c.730_731insA). These mutations have a pathogenic and damaging influence on the ABHD5 protein structure and function. During the 2 year clinical follow-up one patient died of severe chest infection; he had severe phenotype. There is no genotype–phenotype correlation in CDS. Therapy with low fat diet, MCT oil, Vit E and ursodeoxycholic acid has promising results in CDS.

Conclusion

Non-bullous ichthyosiform erythroderma, steatohepatitis and Jordan’s anomaly are consistent findings in all cases of CDS. It is suggested that an accurate diagnosis of CDS should be based on combination of clinical features and pathognomonic ABHD5 mutations. More studies should be carried out to identify population-specific genetic mutations for the rapid and cost-effective diagnosis of CDS.

Maternal Isodisomy of Chromosome 3 Combined with a De Novo Mutation in the ABHD5 Gene Causes Autosomal Recessive Chanarin-Dorfman Syndrome

Autosomal recessive Chanarin-Dorfman syndrome (CDS, MIM #275630) is defined as a neutral lipid storage disease with ichthyosis (NLSDI) due to an accumulation of lipid droplets in a variety of different tissues including liver and muscle cells, leucocytes, fibroblasts and nerve cells It is caused by biallelic mutations in the abhydrolase domain containing 5 gene (ABHD5, MIM *604780) which is localized on the short arm of chromosome 3. Here we report an 18 month-old girl in whom we have identified the homozygous ABHD5 mutation c.700C > T, p.(Arg234*). Since none of the parents carried this point mutation, parentage was confirmed by microsatellite marker analysis. Suspected uniparental disomy (UPD) was confirmed by microsatellite genotyping over the entire chromosome 3 and indicated a maternal origin. UPD is an extremely rare event that is not necessarily pathogenic, but may cause disease if the affected chromosome contains genes that are imprinted. Here we report the first case of Chanarin-Dorfman syndrome due to a de novo ABHD5 mutation in the maternal germ cell, combined with a maternal uniparental isodisomy of chromosome 3. This case demonstrates that genetic analysis of the patient and both parents is crucial to provide correct genetic counseling.

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.

Recurrent N209* ABHD5 mutation in two unreported families with Chanarin Dorfman Syndrome

ABHD5 protein is widely involved in lipid and energy homeostasis. Mutations in the ABHD5 gene are associated with the onset of Neutral Lipid Storage Disease with Ichthyosis (NLSDI), historically known as Chanarin Dorfman Syndrome (CDS). CDS is a rare autosomal recessive lipid storage disease, characterized by non-bullous congenital ichthyosiform eritrhoderma (NCIE), hepatomegaly and liver steatosis. Myopathy, neurosensory hearing loss, cataracts, nystagmus, strabismus, and mental impairment are considered additional findings. To date, 151 CDS patients have been reported all over the world. Here we described two additional families with patients affected by CDS from Turkey. Our patients were a 42 and 22-years old men, admitted to the Hospital for congenital ichthyosis. Hepatic steatosis and myopathy were also detected in both patients. ABHD5 molecular analysis revealed the presence of N209* mutation. Our data enlarge the cohort of CDS patients and provide a revision of muscle clinical findings for this rare inborn error of neutral lipid metabolism.

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.

SDR9C7 plays an essential role in skin barrier function by dehydrogenating acylceramide for covalent attachment to proteins

Among the components of the barrier structure of the stratum corneum in human skin, the corneocyte lipid envelope (CLE) is extremely important for the skin barrier. The importance of the CLE and esterified ω-hydroxy sphingosine (CerEOS), its main precursor, has been suggested from the fact that mutations in a number of genes involved in CerEOS synthesis and CLE formation have been identified as genetic causes of congenital ichthyoses, which are severe genetic skin disorders. However, the molecule/mechanism involved in the covalent binding of CerEOS to proteins on the outer surface of the cornified cell envelope had been a missing part. Very recently, we proposed new potential modes of protein binding by covalent reactions of CerEOS-epoxy-enone. We revealed the biochemical function of short-chain dehydrogenase/reductase family 9C member 7 (SDR9C7), encoded by SDR9C7, as catalyzing the dehydrogenation of the lipoxygenase products that are esterified in CerEOS. Epoxy-enone produced by SDR9C7 covalently binds to proteins on the outer extracellular surface of the cornified cell envelope. Importantly, our recent striking findings were derived from the detailed lipid analysis of only one ARCI patient with SDR9C7 mutation. The combination of detailed analyses of precious samples from a rare patient and the establishment of corresponding animal models is an effective and powerful tool for analyzing rare inherited diseases. This review summarizes this newly revealed mechanism in skin barrier formation, describes the characteristic features of patients with SDR9C7 mutations, and introduces the clinical value of non-invasive analyses for patients with very rare intractable skin diseases.

Sequence analysis and structure prediction of ABHD16A and the roles of the ABHD family members in human disease

Abhydrolase domain containing 16A (ABHD16A) is a member of the α/β hydrolase domain-containing (ABHD) protein family and is expressed in a variety of animal cells. Studies have shown that ABHD16A has acylglycerol lipase and phosphatidylserine lipase activities. Its gene location in the main histocompatibility complex (MHC) III gene cluster suggests that this protein may participate in the immunomodulation of the body. The results of studies investigating nearly 20 species of ABHDs reveal that the ABHD proteins are key factors in metabolic regulation and disease occurrence and development. In this paper, we summarize the related progress regarding the function of ABHD16A and other ABHD proteins. A prediction of the active sites and structural domains of ABHD16A and an analysis of the amino acid sites are included. Moreover, we analysed the amino acid sequences of the ABHD16A molecules in different species and provide an overview of the related functions and diseases associated with these proteins. The functions and diseases related to ABHD are systematically summarized and highlighted. Future research directions for studies investigating the functions and mechanisms of these proteins are also suggested. Further studies investigating the function of ABHD proteins may further confirm their positions as important determinants of lipid metabolism and related diseases.

Clinical and genetic characterization of a Chanarin Dorfman Syndrome patient born to diseased parents

Background

Chanarin Dorfman Syndrome (CDS) is a rare autosomal recessive disorder characterized by ichthyosiform non-bullous erythroderma and variable involvement of the liver and the neuromuscular system. In CDS patients, the accumulation of neutral lipids inside cytoplasmic lipid droplets has been demonstrated in different tissues. To date, ninety families with this disease have been described worldwide; most of them are from Mediterranean countries.

Case presentation

In this report, we describe a consanguineous Turkish family with typical features of CDS. The parents are first cousins and are both diseased. At the age of eight, their child presented CDS with non-bullous congenital ichthyosiform erythroderma, hepatosteatosis, hepatomegaly and ectropion. Electromyographic examination is compatible with myopathy. A five-year-old cousin of the child is also affected by CDS. She was born to non-affected consanguineous parents. Mutation analysis of the ABHD5 gene revealed the previously reported mutation, N209X, which is the most frequent in Turkish patients. Lipid vacuoles, also known as Jordan’s anomaly, are detectable in their leucocytes.

Conclusions

To the best of our knowledge, this is the first report of a CDS family in which both parents and their child are affected by CDS. To date, the child does not present a more severe clinical phenotype compared with those of his relatives or other CDS patients of the same age. These findings suggest that high levels of triacylglycerol accumulation, that may be supposed to be present in high amount inside the ooplasm, did not affect embryo development and foetal growth.

Electronic supplementary material

The online version of this article (10.1186/s12881-018-0610-0) contains supplementary material, which is available to authorized users.