Correlation of genotype and phenotype in 32 patients with hereditary hemochromatosis in China

SLC40A1-related hemochromatosis associated with a p.Y333H mutation in mainland China: a pedigree report and literature review

BACKGROUND

Haemochromatosis is a genetic disease characterized by the excessive deposition of iron in various tissues and organs, eventually results in organ damage including cirrhosis, diabetes, cardiomyopathy, etc. SLC40A1-related haemochromatosis is associated with gain-of-function mutations in the SLC40A1 gene, which encodes ferroportin. While sporadic reports of this condition exist in mainland China, the understanding of the phenotype and genetic pattern associated with the SLC40A1 p.Y333H mutation remains incomplete.

CASE PRESENTATION

We report a pedigree with heterozygous p.Y333H mutation in Chinese Han population. The proband is a 64-year-old man complaining of persistent abnormality of liver enzyme levels for 1 year, with a history of knee joint pain, diabetes and skin pigmentation. He displayed markedly elevated serum ferritin level and transferrin saturation. Magnetic resonance imaging showed iron deposition in the liver, spleen, and pancreas, along with cirrhosis and splenomegaly. Whole exome sequencing identified a heterozygous allelic variant c.997T > C (p.Y333H). Genetic screening of family members identified four first-degree relatives and three second-degree relatives having the same mutation. Additional cases with this mutation from two published studies were included. Among the probands and screened relatives, all eight males aged over 30 y had ferritin level > 1000 µg/L, transferrin saturation > 90%. Four patients with organ damage in the present study received therapeutic phlebotomy, alleviating clinical symptoms and improving in transferrin saturation and serum ferritin.

CONCLUSIONS

This study reports the largest pedigree with heterozygous SLC40A1 p.Y333H mutation in the Chinese population to date. In Chinese families, males over 30 years old with hemochromatosis due to SLC40A1 p.Y333H mutation exhibit severe iron overload phenotypes.

Chronic hepatitis B complicated with secondary hemochromatosis was cured clinically: A case report

Chronic hepatitis B (CHB) often causes iron overload in the liver but rarely causes severe secondary hemochromatosis (SH). A 48-year-old man was infected with CHB via vertical transmission. For 21 years, nonstandard treatment with second-line hepatitis B antiviral drugs has been administered. Repeated abnormalities in the liver transaminase function and continuous low-level replication of the hepatitis B virus (HBV) have been detected. The skin had turned black 5 years back. Biochemical tests and imaging revealed the presence of hemochromatosis. A liver biopsy suggested severe iron overload. Two genetic tests ruled out hereditary hemochromatosis. The patient was diagnosed with SH and treated with 400 ml bloodletting once per week and an iron-chelating agent. After 12 weeks, liver function was normal, and the skin turned white. First, hepatitis B surface antigen (HBsAg) was lost, and HBV DNA was copied at low levels. The patient was diagnosed with an occult hepatitis B infection. HBV DNA was undetectable after 4 weeks of antiviral treatment with tenofovir. Upon reviewing the patient’s medical history, hemochromatosis was believed to be related to CHB with chronic inflammatory damage and no complete virological response. Improvements in hemochromatosis may promote HBsAg disappearance.

HAMP as a Potential Diagnostic, PD-(L)1 Immunotherapy Sensitivity and Prognostic Biomarker in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) remains a global medical problem. Programmed cell death protein 1 (PD-1) is a powerful weapon against many cancers, but it is not sensitive to some patients with HCC. We obtained datasets from the Gene Expression Omnibus (GEO) database on HCC patients and PD-1 immunotherapy to select seven intersecting DEGs. Through Lasso regression, two intersecting genes were acquired as predictors of HCC and PD-1 treatment prognosis, including HAMP and FOS. Logistic regression was performed to build a prediction model. HAMP had a better ability to diagnose HCC and predict PD1 treatment sensitivity. Further, we adapted the support vector machine (SVM) technique using HAMP to predict triple-classified outcomes after PD1 treatment in HCC patients, which had an excellent classification ability. We also performed external validation using TCGA data, which showed that HAMP was elevated in the early stage of HCC. HAMP was positively correlated with the infiltration of 18 major immune cells and the expression of 2 important immune checkpoints, PDCD1 and CTLA4. We discovered a biomarker that can be used for the early diagnosis, prognosis and PD1 immunotherapy efficacy prediction of HCC for the first time and developed a diagnostic model, prognostic model and prediction model of PD1 treatment sensitivity and treatment outcome for HCC patients accordingly.

DENND3 p.L708V activating variant is involved in the pathogenesis of hereditary hemochromatosis via the RAB12/TFR2 signaling pathway

PURPOSE

Pathogenic variants in HFE and non-HFE genes have been identified in hereditary hemochromatosis (HH) in different patient populations, but there are still a considerable proportion of patients with unexplained primary iron overload. We recently identified in Chinese patients with unexplained primary iron overload a recurrent p.L708V variant in the differentially expressed in normal and neoplastic cells domain 3 (DENND3) gene, functioning as a guanine nucleotide exchange factor for small GTpase Rab12 which down-regulates TfR expression in mice. We aim to investigate the pathogenicity and the underlying mechanism of the DENND3 p.L708V variant in HH patients.

METHODS

Patients with primary iron overload were analyzed for DENND3 p.L708V. TFR2 and hepcidin expression in livers were examined in HH patients harboring DENND3 p.L708V. The effects of DENND3 p.L708V on RAB12/TFR2 and downstream iron metabolic pathways were investigated in vitro and in vivo.

RESULTS

Six of 31 patients with HH (19.35%) harbored the DENND3 p.L708V variant. The expression of TFR2 and hepcidin was decreased in the liver of HH patients with DENND3 p.L708V. Cells transfected with the DENND3 p.L708V vector showed up-regulation of RAB12 expression and TFR2 degradation in lysosomes, and down-regulation of the pSMAD1/5 and hepcidin. Mice models infected with adeno-associated virus expressing DENND3 p.L708V variant showed higher total serum iron concentrations and decreased HAMP level, increased amount of iron accumulation and the down-regulated of TFR2 expression in the liver.

CONCLUSIONS

The DENND3 p.L708V activating variant down-regulates hepcidin expression through the DENND3/RAB12/TFR2 axis, which may represent a potential novel pathogenic factor of HH.

Magnetic resonance spectroscopy for quantification of liver iron deposition in hereditary hemochromatosis of a Chinese family: Four case reports

RATIONALE

Hereditary hemochromatosis (HH) is a major cause of liver iron overload. The gold standard for the diagnosis of liver iron overload is the histopathological analysis of a liver sample collected by biopsy. The biopsy procedure is both invasive and painful and carries some risks of complications. The multi-echo single-voxel magnetic resonance spectroscopy (HISTO) technique can be used for noninvasive, quantitative assessment of liver iron overload.

PATIENT CONCERNS

We report 4 Chinese Han men, who were relatives. Patient A was admitted with diabetes and presented with thrombocytopenia and skin hyperpigmentation. The other patients had no specific clinical presentation.

DIAGNOSES

Patient A was suspected of having iron in the liver on routine magnetic resonance imaging, therefore, further HISTO, laboratory testing, and liver biopsy were performed, which confirmed iron metabolic abnormalities. Furthermore, we identified hepatic iron deposition using HISTO and laboratory testing of his son and 2 brothers. Combined with symptoms, auxiliary examinations, and liver biopsy, HH was considered.

INTERVENTIONS

As the 4 patients had no other discomfort other than patient A who had diabetes, patient A was placed on therapy comprising the insulin pump, acarbose, and platelet booster capsule.

OUTCOMES

After treatment, the diabetic symptoms of patient A improved. The patient and his relatives were regularly followed-up for HH.

LESSONS

HH should be considered when hepatic iron deposition is suspected by routine magnetic resonance, as the HISTO sequence can quantitate liver iron deposition and leads to a promising diagnosis. HISTO is of great value in familial cases, especially in young patients requiring long-term follow-up.

Juvenile Hemochromatosis due to a Homozygous Variant in the HJV Gene

Hemochromatosis type 2 or juvenile hemochromatosis has an early onset of severe iron overload resulting in organ manifestation such as liver fibrosis, cirrhosis, cardiomyopathy, arthropathy, hypogonadism, diabetes, osteopathic medicine, and thyroid abnormality, before age of 30. Juvenile hemochromatosis type 2a and 2b is an autosomal recessive disease caused by pathogenic variants in HJV and HAMP genes, respectively. We report a child with hepatic iron overload and family history of hemochromatosis. We aim to raise awareness of juvenile hemochromatosis, especially in families with a positive family history, as early diagnosis and treatment may prevent organ involvement and end-stage disease. The purpose of this study was to identify the gene variant that causes the disease. The genetic study was performed with a targeted gene panel: HFE, HJV, HAMP, TFR2, SLC40A1, FTL, and FTH1. We identified the variant c.309C > G (p.Phe103Leu) in the HJV gene in the homozygous state in the patient.

Turner syndrome with primary myelofibrosis, cirrhosis and ovarian cystic mass: A case report

BACKGROUND

Turner syndrome (TS) with leukemia is a complicated clinical condition. The clinical course and outcome of these patients are poor, so the treatment and prognosis of TS with hematological malignancies deserve our attention.

CASE SUMMARY

Here, we report a case of a 20-year-old woman diagnosed with TS, primary myelofibrosis (PMF), cirrhosis, and an ovarian cystic mass. This is the first report on the coexistence of TS and PMF with the MPL and SH2B3 mutations. The patient was diagnosed with cirrhosis of unknown cause, splenomegaly and severe gastroesophageal varices. Additionally, an ovarian cystic mass caused the patient to appear pregnant. The patient was treated with the JAK2 inhibitor-ruxolitinib according to peripheral blood cells, although myelofibrosis was improved, the splenomegaly did not reduce. Moreover, hematemesis and melena occasionally occurred.

CONCLUSION

Ruxolitinib may clearly reduce splenomegaly. Though myelofibrosis was improved, cirrhosis and splenomegaly in this case continued to worsen. Effective treatment should be discussed.