Expanding the molecular diversity and phenotypic spectrum of glycerol 3-phosphate dehydrogenase 1 deficiency

Glycerol-3-Phosphate Dehydrogenase 1 Deficiency and Steatotic Liver Disease in Children: Our Cases and Review of Literature

Introduction

Glycerol-3-phosphate dehydrogenase 1 (GPD1) deficiency is an autosomal recessive disorder causing hypertriglyceridemia, hepatomegaly, fatty liver, and hepatic fibrosis in infancy. It is an under-recognized cause of pediatric steatotic liver disease (SLD) with only 36 cases reported worldwide.

Method

We analyzed the clinical profile of our five cases diagnosed by exome sequencing (ES) and reviewed the published cases till December 2023 using PubMed search.

Results

Five unrelated boys (6-24months) presented with hepatomegaly, hypertriglyceridemia, transaminase elevation, and fatty liver. ES revealed compound heterozygous mutations in two and homozygous mutation in three including two novel mutations (c.917T >C, c.905C > G). All received supportive therapy, and fenofibrate was successfully used in one case for progressive hypertriglyceridemia. Globally, 36 cases (age at diagnosis: 6 [1-164 months]) have been reported. Majority had hepatomegaly (94.4%), 22.2% each had splenomegaly and growth failure. Hypertriglyceridemia (97.2%) was nearly universal, 100% had fatty liver, and hypoglycaemia (11.2%) was uncommon. Liver biopsy (n = 18) demonstrated steatosis in all, fibrosis in 94.4%, and cirrhosis in 22.2%. During follow-up (11-376 months), hepatomegaly resolved in 35.2%, triglycerides, and transaminases normalized in 29.1% and 31.5%, respectively. No pancreatitis, cardiac events, or liver decompensation was reported.

Conclusion

GPD1 is an uncommon cause of SLD, raised transaminases and hypertriglyceridemia in young children. Diagnosis is confirmed by genetic testing. Supportive therapy, parental counseling about the disease nature and close follow-up is recommended.

Identification of a novel heterozygous GPD1 missense variant in a Chinese adult patient with recurrent HTG-AP consuming a high-fat diet and heavy smoking

BACKGROUND

Glycerol-3-phosphate dehydrogenase 1 (GPD1) gene defect can cause hypertriglyceridemia (HTG), which usually occurs in infants. The gene defect has rarely been reported in adult HTG patients. In the present study, we described the clinical and functional analyses of a novel GPD1 missense variant in a Chinese adult patient with recurrent hypertriglyceridemia‑related acute pancreatitis (HTG-AP), consuming a high-fat diet and smoking heavily.

METHODS

Exome sequencing was used to analyze the DNA of the adult patient's blood sample. It was found that there was a new variant of GPD1 gene-p.K327N, which was verified by gold standard-sanger sequencing method. In vitro, the corresponding plasmid was constructed and transfected into human renal HEK-293T cells, and GPD1 protein levels were detected. A biogenic analysis was performed to study the population frequency, conservation, and electric potential diagram of the new variant p.K327N. Finally, the previously reported GPD1 variants were sorted and their phenotypic relationships were compared.

RESULTS

A novel heterozygous variant of GPD1, p.K327N (c.981G > C), was found in the proband. Furthermore, the patient's daughter carried this variant, whereas his wife did not carry the variant. The proband with obesity suffered eight episodes of HTG-AP from the age of 36 years, and each onset of AP was correlated to high-fat diet consumption and heavy smoking. In vitro, this variant exerted a relatively mild effect on GPD1 functions, which were associated with its effect upon secretion (~ 25% of secretion decreased compared with that of the wild-type); thus, eventually impairing protein synthesis. Additionally, 36 patients with GPD1 variants found in previous studies showed significant transient HTG in infancy. The proband carrying the GDP1 variant was the first reported adult with recurrent HTG-AP.

CONCLUSION

We identified a novel GPD1 variant, p.K327N, in a Chinese adult male patient with recurrent HTG-AP. The variant probably exerted a mild effect on GPD1 functions. The heterozygosity of this GPD1 variant, in addition to high-fat diet consumption and heavy smoking, probably triggered HTG-AP in the patient.

A very rare cause of hypertrygliseridemia in infancy: a novel mutation in glycerol-3-phosphate dehydrogenase 1 (GPD1) gene

OBJECTIVES

Transient infantile hypertriglyceridemia (HTGTI) is caused by mutations in the glycerol-3-phosphate dehydrogenase 1 (GPD1) gene. HTGTI is characterized by hypertriglyceridemia, hepatomegaly, hepatic steatosis and fibrosis in infancy. Here, we reported first Turkish HTGTI patient with a novel mutation of GPD1, having hypertriglyceridemia, hepatomegaly, growth retardation and hepatic steatosis. He is the first case who needs transfusion until 6th month in GPD1.

CASE PRESENTATION

A 2-month-27-day-old boy, who had growth retardation, hepatomegaly and anemia suffered to our hospital with vomiting. Triglyceride level was 1603 mg/dL (n<150). Liver transaminases were elevated and hepatic steatosis was developed. He needed transfusion with erythrocyte suspension until 6th month. Etiology could not be elucidated by clinical and biochemical parameters. A novel homozygous c.936_940del (p.His312GlnfsTer24) variant was detected in the GPD1 gene by Clinical Exome Analysis.

CONCLUSIONS

GPD1 deficiency should be investigated in the presence of unexplained hypertriglyceridemia and hepatic steatosis in children especially in infants.

Clinical characteristics and variant analyses of transient infantile hypertriglyceridemia related to GPD1 gene

Objective: Our study aims to summarize and analyze the clinical characteristics of transient infantile hypertriglyceridemia (HTGTI) and variants in the glycerol-3-phosphate dehydrogenase 1 (GPD1) gene and the effect of HTGTI on the protein structure of GPD1.

Methods: Retrospective analysis, using the general data, symptoms, signs, and auxiliary examinations, was performed on patients with HTGTI, which were confirmed by genetic testing in our hospital and reported cases online. The clinical data were analyzed using statistical and bioinformatic approaches.

Results: A total of 31 genetically confirmed HTGTI patients were collected from our hospital and cases reported in the literature. The clinical manifestations showed the median age of onset was 6.0 (1.9, 12.0) months. All the patients had normal psychiatric status, but 22.6% of them presented growth retardation and short stature, 93.5% had hepatomegaly, and 16.1% had splenomegaly. Just a few children were reported with jaundice, cholestasis, and obesity (3.2–6.5%). The laboratory investigations showed that 96.8% of them had hypertriglyceridemia (HTG) with a median level of 3.1 (2.1, 5.5) mmol/L, but only 30.0% had returned to normal during follow-up. In addition, 93.5% of patients had elevated alanine aminotransferase (ALT) with an average level of 92.1 ± 43.5 U/L, while 38.7% had hypercholesterolemia. Upon abdominal imaging, all patients presented fatty liver and liver steatosis, with 66.7% of patients showing hepatic fibrosis. Statistical differences in triglyceride (TG) level were observed in the ≤6 months group compared with the older groups and in the 13 months to 6 years group with &gt;6 years group (H = 22.02, P &lt; 0.05). The restricted cubic spline model showed that severe HTG decreased in the early stage of infants to the normal level; however, it rebounded again to a mild or moderate level after the following days. The genetic test revealed that the main variant types of the GPD1 gene were missense variants (51.6%), followed by splicing variants (35.5%) and nonsense variants (12.9%). Of patients, 87.1% had homozygous variants, with the most frequent loci being c.361-1G &gt; C and c.895G &gt; A.

Conclusion: The common manifestations of HTGTI were HTG, hepatomegaly, elevated liver transaminases, and hepatic steatosis in early infancy. However, the recurrence of aberrant HTG may pose long-term detrimental effects on HTGTI patients.

Identifying Patients with Familial Chylomicronemia Syndrome Using FCS Score-Based Data Mining Methods

Background: There are no exact data about the prevalence of familial chylomicronemia syndrome (FCS) in Central Europe. We aimed to identify FCS patients using either the FCS score proposed by Moulin et al. or with data mining, and assessed the diagnostic applicability of the FCS score. Methods: Analyzing medical records of 1,342,124 patients, the FCS score of each patient was calculated. Based on the data of previously diagnosed FCS patients, we trained machine learning models to identify other features that may improve FCS score calculation. Results: We identified 26 patients with an FCS score of ≥10. From the trained models, boosting tree models and support vector machines performed the best for patient recognition with overall AUC above 0.95, while artificial neural networks accomplished above 0.8, indicating less efficacy. We identified laboratory features that can be considered as additions to the FCS score calculation. Conclusions: The estimated prevalence of FCS was 19.4 per million in our region, which exceeds the prevalence data of other European countries. Analysis of larger regional and country-wide data might increase the number of FCS cases. Although FCS score is an excellent tool in identifying potential FCS patients, consideration of some other features may improve its accuracy.

Case of GPD1 deficiency causing hypertriglyceridaemia and non-alcoholic steatohepatitis

We report a case of a young girl of South Asian descent presented with faltering growth, hepatomegaly, hypertriglyceridaemia and raised transaminases. Subsequent ultrasound scans identified fatty infiltration in her liver, and a liver biopsy showed fibrosis and steatosis. The patient's serum triglycerides normalised without intervention by the age of 28 months. At age 6, whole-exome sequencing of the patient's genome identified novel homozygous variants in the glycerol-3-phosphate dehydrogenase 1 (GPD1) gene, GPD1 c.500G>A (p.Gly167Asp), leading to a diagnosis of GPD1 deficiency.

Transient infantile hypertriglyceridaemia due to homozygous mutation in GPD1 presenting in childhood with hepatic adenoma

Hypertriglyceridaemia in infancy is usually secondary to underlying metabolic disorder which usually has a genetic basis unlike the adult population. One such recently described entity is transient infantile hypertriglyceridaemia (HTGTI). In this disorder, mutation in glycerol-3-phosphate (G3P) dehydrogenase gene leads to deficiency of G3P dehydrogenase resulting in hypertriglyceridaemia and hepatomegaly. Clinical features tend to improve with age but may develop fibrosis. Our patient presented in infancy with hypoglycaemia, hepatomegaly, high transaminases and hypertriglyceridaemia. Limited genetic test for glycogen storage disorder was negative and was kept under follow-up. On follow-up, he developed hepatic lesion and his hepatomegaly with hypertriglyceridaemia persisted. There are only a few cases reported worldwide and none has reported development of adenoma so far. This could be the first report of development of adenoma in transient HTGTI.

Case Report: Identification of a Novel Homozygous Mutation in GPD1 Gene of a Chinese Child With Transient Infantile Hypertriglyceridemia

Transient infantile hypertriglyceridemia is a rare autosomal recessive disorder characterized by hypertriglyceridemia, hypohepatia, hepatomegaly, hepatic steatosis and fibrosis in infancy. Mutations in GPD1 gene are considered the causative factor but the underlying mechanism of this disorder is still enigmatic. To date, only 24 different GPD1 mutations have been reported in the literature worldwide with transient infantile hypertriglyceridemia or relevant conditions. Here we report a Chinese girl who developed hepatomegaly hepatic steatosis, elevated transaminase and hypertriglyceridemia from the age of 4 months. A novel homozygous variant c.454C>T (p.Q152*) was found in GPD1 gene by next-generation sequencing. This patient is the 3rd Asian reported with transient infantile hypertriglyceridemia. We summarized the clinical presentations of transient infantile hypertriglyceridemia and also expanded the spectrum of disease-causing mutations in GPD1.

Transient infantile hypertriglyceridemia with jaundice: A case report

RATIONALE

Transient infantile hypertriglyceridemia (HTGTI) is a rare autosomal recessive inherited disease caused by inactivating mutations in the glycerol-3-phosphate dehydrogenase 1 gene. To date, only a few patients have been reported worldwide. The symptoms of the affected individuals present a certain degree of transient hypertriglyceridemia, hepatomegaly, elevated liver enzymes, persistent fatty liver and hepatic fibrosis in early infancy. However, the clinical characteristics and pathogenesis of this disease are remain unclear.

PATIENT CONCERNS

A one month and twenty-five days old girl was admitted to hospital because of persisted jaundice and hepatomegaly for fifty days.

DIAGNOSE

The girl was diagnosed with HTGTI coincident with a noval mutation in glycerol-3-phosphate dehydrogenase 1.

INTERVENTION

She was advised to take low-fat diet and supplement of medium-chain fatty acids.

OUTCOMES

Her jaundice was gradually normal at the age of 4 months without any treatment, and hypertriglyceridemia were normal at the age of 13 months, but still had elevated transaminases and hepatic steatosis.

LESSONS

Jaundice may be a novel phenotype in HTGTI. The report contributes to the expansion of HTGTI's gene mutation spectrum and its clinical manifestations.

Successful fenofibrate therapy for severe and persistent hypertriglyceridemia in a boy with cirrhosis and glycerol-3-phosphate dehydrogenase 1 deficiency

Glycerol-3-phosphate dehydrogenase 1 deficiency is a rare autosomal recessive disorder caused by mutations in the GPD1 gene (GPD1; OMIM*138420). Very few cases are reported in literature. It usually manifests in early infancy with transient hypertriglyceridemia, hepatomegaly, steatosis, and fibrosis. We report the case of a 16-year-old boy followed since the age of 1 year for hepatomegaly, elevated liver enzymes, and persistent hypertriglyceridemia. Abdominal ultrasound showed diffuse liver echogenicity and liver biopsy disclosed cirrhosis with micro and macrovesicular steatosis. Next-generation sequencing for metabolic and genetic liver diseases was conducted with the identification of the homozygous mutation c.895G>A in GPD1 gene resulting in the aminocidic substitution p.G299R. Considering the persistent and progressive increase of plasma triglycerides, fenofibrate treatment was started at 15 years of age allowing triglyceride level reduction in the following 1-year follow-up.

Clinical Application of Genome and Exome Sequencing as a Diagnostic Tool for Pediatric Patients: a Scoping Review of the Literature

PURPOSE

Availability of clinical genomic sequencing (CGS) has generated questions about the value of genome and exome sequencing as a diagnostic tool. Analysis of reported CGS application can inform uptake and direct further research. This scoping literature review aims to synthesize evidence on the clinical and economic impact of CGS.

METHODS

PubMed, Embase, and Cochrane were searched for peer-reviewed articles published between 2009 and 2017 on diagnostic CGS for infant and pediatric patients. Articles were classified according to sample size and whether economic evaluation was a primary research objective. Data on patient characteristics, clinical setting, and outcomes were extracted and narratively synthesized.

RESULTS

Of 171 included articles, 131 were case reports, 40 were aggregate analyses, and 4 had a primary economic evaluation aim. Diagnostic yield was the only consistently reported outcome. Median diagnostic yield in aggregate analyses was 33.2% but varied by broad clinical categories and test type.

CONCLUSION

Reported CGS use has rapidly increased and spans diverse clinical settings and patient phenotypes. Economic evaluations support the cost-saving potential of diagnostic CGS. Multidisciplinary implementation research, including more robust outcome measurement and economic evaluation, is needed to demonstrate clinical utility and cost-effectiveness of CGS.

Precision toxicology shows that troxerutin alleviates ochratoxin A-induced renal lipotoxicity

Lipotoxicity is the most common cause of severe kidney disease, with few treatment options available today. Precision toxicology can improve detection of subtle intracellular changes in response to exogenous substrates; thus, it facilitates in-depth research on bioactive molecules that may interfere with the onset of certain diseases. In the current study, troxerutin significantly relieved nephrotoxicity, increased endurance, and improved systemic energy metabolism and renal inflammation in OTA-induced nephrotic mice. Lipidomics showed that troxerutin effectively reduced the levels of triglycerides, phosphatidylcholines, and phosphatidylethanolamines in nephropathy. The mechanism was partly attributable to troxerutin in alleviating the aberrantly up-regulated expression of sphingomyelinase, the cystic fibrosis transmembrane conductance regulator, and chloride channel 2. Renal tubular epithelial cells, the main site of toxin-induced accumulation of lipids in the kidney, were subjected to transcriptomic profiling, which uncovered several metabolic factors relevant to aberrant lipid and lipoprotein metabolism. Our work provides new insights into the molecular features of toxin-induced lipotoxicity in renal tubular epithelial cells in vivo and demonstrates the function of troxerutin in alleviating OTA-induced nephrosis and associated systemic energy metabolism disorders.-Yang, X., Xu, W., Huang, K., Zhang, B., Wang, H., Zhang, X., Gong, L., Luo, Y., He, X. Precision toxicology shows that troxerutin alleviates ochratoxin A-induced renal lipotoxicity.

A novel homozygous mutation in the glycerol-3-phosphate dehydrogenase 1 gene in a Chinese patient with transient infantile hypertriglyceridemia: a case report

Background

Transient infantile hypertriglyceridemia (HTGTI) is an autosomal recessive disorder caused by mutations in the glycerol-3-phosphate dehydrogenase 1 (GPD1) gene.

Case presentation

We report a case of HTGTI in a Chinese female infant. She presented with hepatomegaly, hypertriglyceridemia, moderately elevated transaminases, and hepatic steatosis at 3.5 months of age. A novel mutation c.523C>T, p. (Q175*) was identified in GPD1. The patient was a homozygote and her parents were heterozygous for the mutation. Ultrastructural study showed intrahepatocytic lipid droplets.

Conclusions

This is the first reported case of HTGTI in Chinese, expanding the worldwide distribution of HTGTI and the mutation spectrum of GPD1.

Electronic supplementary material

The online version of this article (10.1186/s12876-018-0827-6) contains supplementary material, which is available to authorized users.