Cholesteryl ester storage disease of clinical and genetic characterisation: A case report and review of literature

BACKGROUND Cholesteryl ester storage disease(CESD)is a rare genetic disease.Its symptoms and severity are highly variable.CESD is a systemic disease that can lead to the accumulation of fat and inflammation in the liver,as well as gastrointestinal and cardiovascular disease.The majority of patients require liver transplantation due to decompensated cirrhosis.Enzyme replacement therapy has been approved based on a randomized trial.Our study aims to clinically and genetically evaluate two siblings with CESD who underwent liver transplantation,as well as their first-degree family members.CASE SUMMARY The siblings were compound heterozygous for the missense variant in LIPA exon 8,c.894G>A,(p.Gln298Gln)and a single base pair deletion,c.482del(p.Asn161Ilefs*19).Analyses of single nucleotide polymorphisms showed variants with an increased risk of fatty liver disease and fibrosis for both patients.Clinically,both patients show signs of recurrence of CESD in the liver after transplantation and additional gastrointestinal and cardiovascular signs of CESD.Three family members who were LIPA heterozygous had a lysosomal acid lipase activity below the reference value.One of these carriers,a seven-year-old boy,was found to have severe dyslipidemia and was subsequently treated with statins.CONCLUSION Our study underlines that CESD is a multi-organ disease,the progression of which may occur post-liver transplantation.Our findings underline the need for monitoring of complications and assessment of possible further treatment.

Role of lipids in the control of autophagy and primary cilium signaling in neurons

The brain is,after the adipose tissue,the organ with the greatest amount of lipids and diversity in their composition in the human body.In neurons,lipids are involved in signaling pathways controlling autophagy,a lysosome-dependent catabolic process essential for the maintenance of neuronal homeostasis and the function of the primary cilium,a cellular antenna that acts as a communication hub that transfers extracellular signals into intracellular responses required for neurogenesis and brain development.A crosstalk between primary cilia and autophagy has been established;however,its role in the control of neuronal activity and homeostasis is barely known.In this review,we briefly discuss the current knowledge regarding the role of autophagy and the primary cilium in neurons.Then we review the recent literature about specific lipid subclasses in the regulation of autophagy,in the control of primary cilium structure and its dependent cellular signaling in physiological and pathological conditions,specifically focusing on neurons,an area of research that could have major implications in neurodevelopment,energy homeostasis,and neurodegeneration.

Novelα-galactosidase A gene mutation in a Chinese Fabry disease family:A case report

BACKGROUND Fabry disease(FD)is a rare X-linked lysosomal storage disease caused by a deficiency of the enzymeα-galactosidase A.CASE SUMMARY Herein,we analyzed a four-generation Chinese family.The proband is a 57-yearold woman who was diagnosed with left ventricular hypertrophy and atrial fibrillation 7 years ago.Echocardiography showed an end-diastolic diameter of the interventricular septum of 19.9 mm,left ventricular end-diastolic diameter of 63.1 mm,and moderate-to-severe mitral regurgitation.Cardiac magnetic resonance indicated an enlarged left heart and right atrium,decreased left ventricular systolic and diastolic function,a left ventricular ejection fraction of 20%,and thickening of the left ventricular septum.In March 2019,gene and enzyme activity tests confirmed the diagnosis of FD.Her son was diagnosed with FD after gene and enzyme activity assay,and was prescribed agalsidase-βfor enzyme replacement therapy in July 2020.Two sisters of the proband were also diagnosed with FD by genetic testing.Both of them had a history of atrial fibrillation.CONCLUSION A novel mutation was identified in a Chinese family with FD,in which the male patient had a low level of enzyme activity,early-onset,and severe organ involvement.Comprehensive analysis of clinical phenotype genetic testing and enzyme activity testing helped in the diagnosis and treatment of this FD family.

Regulation of lysosomal ion homeostasis by channels and transporters

Lysosomes are the major organelles that carry out degradation functions. They integrate and digest materials compartmental- ized by endocytosis, phagocytosis or autophagy. In addition to more than 60 hydrolases residing in the lysosomes, there are also ion channels and transporters that mediate the flux or transport of H＋, Ca2＋, Na＋, K＋, and C1- across the lysosomal mem- branes. Defects in ionic exchange can lead to abnormal lysosome morphology, defective vesicle trafficking, impaired autoph- agy, and diseases such as neurodegeneration and lysosomal storage disorders. The latter are characterized by incomplete lyso- somal digestion and accumulation of toxic materials inside enlarged intracellular vacuoles. In addition to degradation, recent studies have revealed the roles of lysosomes in metabolic pathways through kinases such as mechanistic target of rapamycin （mTOR） and transcriptional regulation through calcium signaling molecules such as transcription factor EB （TFEB） and cal- cineurin. Owing to the development of new approaches including genetically encoded fluorescence probes and whole endoly- sosomal patch clamp recording techniques, studies on lysosomal ion channels have made remarkable progress in recent years. In this review, we will focus on the current knowledge of lysosome-resident ion channels and transporters, discuss their roles in maintaining lysosomal function, and evaluate how their dysfunction can result in disease.

Progranulin acts as a shared chaperone and regulates multiple lysosomal enzymes

Multifunctional factor progranulin(PGRN)plays an important role in lysosomes,and its mutations and insufficiency are associated with lysosomal storage diseases,including neuronal ceroid lipofuscinosis and Gaucher disease(GD).The first breakthrough in understanding the molecular mechanisms of PGRN as regulator of lysosomal storage diseases came unexpectedly while investigating the role of PGRN in inflammation.Challenged PGRN null mice displayed typical features of GD.In addition,GRN gene variants were identified in GD patients and the serum levels of PGRN were significantly lower in GD patients.PGRN directly binds to and functions as a chaperone of the lysosomal enzyme β-glucocerebrosidase(GCaase),whose mutations cause GD.In addition,its C-terminus containing granulin E domain,termed Pcgin(PGRN C-terminus for GCase Interaction),is required for the association between PGRN and GCase.The concept that PGRN acts as a chaperone of lysosomal enzymes was further supported and extended by a recent article showing that PGRN acts as a chaperone molecule of lysosomal enzyme cathepsin D(CSTD),and the association between PGRN and CSTD is also mediated by PGRN’s C-terminal granulin E domain.Collectively,these reports suggest that PGRN may act as a shared chaperone and regulates multiple lysosomal enzymes.

溶酶体贮积症的防治现状及趋势

随着社会进步和经济发展,儿科疾病谱在逐步改变,出生缺陷的危害性日益突出,国家对遗传病也越来越重视,遗传病的防治正成为公共卫生领域的突出问题之一.