Complex heterozygous mutations in hereditary spherocytosis:A case report

BACKGROUND The aim of this study was to investigate the complex heterozygous mutations of ANK1 and SPTA1 in the same individual and improve our understanding of hereditary spherocytosis(HS)in children.We also hope to promote the application of gene detection technology in children with HS,with the goals of identifying more related gene mutations,supporting the acquisition of improved molecular genetic information to further reveal the pathogenesis of HS in children,and providing important guidance for the diagnosis,treatment,and prevention of HS in children.CASE SUMMARY A 1-year and 5-month-old patient presented jaundice during the neonatal period,mild anemia 8 months later,splenic enlargement at 1 year and 5 months,and brittle red blood cell permeability.Genetic testing was performed on the patient,their parents,and sister.Swiss Model software was used to predict the protein structure of complex heterozygous mutations in ANK1 and SPTA1.Genetic testing revealed that the patient harbored a new mutation in the ANK1 gene from the father and a mutation in the SPTA1 gene from the mother.Combined with the clinical symptoms of the children,it is suggested that the newly discovered complex heterozygous mutations of ANK1 and SPTA1 may be the cause,providing important guidance for revealing the pathogenesis,diagnosis,treatment,and promotion of gene detection technology in children with HS.CONCLUSION This case involves an unreported complex heterozygous mutation of ANK1 and SPTA1,which provides a reference for exploring HS.

Characteristics and Clinical Implication of UGT1A1 Heterozygous Mutation in Tumor

Background:The literature recommends that reduced dosage of CPT-11 should be applied in patients with UGT1 A1 homozygous mutations,but the impact of UGT1 A1 heterozygous mutations on the adverse reactions of CPT-11 is still not fully clear.Methods:A total of 107 patients with UGT1 A1 heterozygous mutation or wild-type,who were treated with CPT-11 from January 2018 to September 2021 in Peking University Third Hospital,were retrospectively enrolled.The adverse reaction spectra of patients with UGT1 A1*6 and UGT1 A1*28 mutations were analyzed.Adverse reactions were evaluated according to National Cancer Institute Common Terminology Criteria for Adverse Events(NCI-CTCAE) 5.0.The efficacy was evaluated according to Response Evaluation Criteria in Solid Tumors(RECIST) 1.1.The genotypes of UGT1 A1*6 and UGT1 A1*28 were detected by digital fluorescence molecular hybridization.Results:There were 43 patients with UGT1 A1*6 heterozygous mutation,26 patients with UGT1 A1*28 heterozygous mutation,8 patients with UGT1 A1*6 and UGT1 A1*28 double heterozygous mutations,61 patients with heterozygous mutation at any gene locus of UGT1 A1*6 and UGT1 A1*28.Logistic regression analysis showed that the presence or absence of vomiting(P=0.013) and mucositis(P=0.005) was significantly correlated with heterozygous mutation of UGT1 A1*28,and the severity of vomiting(P<0.001) and neutropenia(P=0.021) were significantly correlated with heterozygous mutation of UGT1 A1*6.In colorectal cancer,UGT1 A1*6 was significantly correlated to diarrhea(P=0.005),and the other adverse reactions spectrum was similar to that of the whole patient cohort,and efficacy and prognosis were similar between patients with different genotypes and patients treated with reduced CPT-11 dosage or not.Conclusion:In clinical use,heterozygous mutations of UGT1 A1*6 and UGT1 A1*28 are related to the risk and severity of vomiting,diarrhea,neutropenia and mucositis in patients with Pan-tumor and colorectal cancer post CPT-11 therpy.In colorectal cancer,UGT1 A1*6 is significantly related to diarrhea post CPT-11 use,efficacy and prognosis is not affected by various genotypes or CPT-11 dosage reduction.

Child with adenylosuccinate lyase deficiency caused by a novel complex heterozygous mutation in the ADSL gene:A case report

BACKGROUND Adenylosuccinate lyase(ADSL)deficiency is a rare autosomal-recessive defect of purine metabolism caused by mutation of the ADSL gene.It can cause severe neurological impairment and diverse clinical manifestations,including epilepsy.CASE SUMMARY Here,we describe a 3-year-old Chinese boy who had both psychomotor retardation and refractory epilepsy.Magnetic resonance imaging showed myelin hypoplasia.Electroencephalography findings supported a diagnosis of epilepsy.Whole-exon sequencing revealed the presence of a novel complex heterozygous mutation in the ADSL gene:The splicing mutation c.154-3C>G and the missense mutation c.71C>T(p.Pro24Leu).Considering the patient’s clinical presentation and genetic test results,the complex heterozygous mutation was predicted to prevent both ADSL alleles from producing normal ADSL,which may have led to ADSL deficiency.Finally,the child was diagnosed with ADSL deficiency.CONCLUSION We identified a novel complex heterozygous mutation in the ADSL gene associated with ADSL deficiency,thus expanding the known spectrum of pathogenic mutations that cause ADSL deficiency.Additionally,we describe epilepsy that occurs in patients with ADSL deficiency.

Digenic heterozygous mutations in EYS/LRP5 in a Chinese family with retinitis pigmentosa

Dear Editor,I am Dr.Ji-Hong Wu,from the Department of Ophthalmology,Eye＆ENT Hospital of Fudan University,China.I write to present a case report of retinitis pigmentosa（RP）caused by novel digenic heterozygous mutations in a Chinese family.

Compound heterozygous mutation in two unrelated cases of Chinese spinal muscular atrophy patients

Background Infantile proximal spinal muscular atrophy （SMA） is a common autosomal recessive neuromuscular disorder. Approximately 90-95% cases of SMA result from homozygous deletion of survival motor neuron gene 1（SMN1） and 5% cases are caused by compound heterozygous mutation （a SMN1 deletion on one allele and a subtle mutation on the other allele）.Methods In this research, two unrelated patients were clinically diagnosed according to the criteria of proximal SMA. Genetic diagnosis was performed to detect the homozygous deletion of exon 7 of SMN1 by PCR-restriction fragment length polymorphism （RFLP） and genomic sequencing. Multiplex ligation-dependent probe amplification （MLPA） analysis was carried out to measure copy numbers of SMN1, SMN2 and neuronal apoptosis inhibitor protein （NAIP） in the patients. Further sequencing of SMN1allele-specific PCR （AS-PCR） and SMN1 clones were also performed to analyze the point mutation of SMN1 gene. Additionally,the pedigree analysis of these two families was carried out to identify the transmission of the mutation.Results The inconsistent results using PCR-RFLP and genomic sequencing showed homozygous deletion of exon 7 of SMN1 and heterozygous deletion accompanied with a suspicious mutation in SMN1 gene, respectively. MLPA analysis of these two cases exhibited one SMN1 copy deletion. One identical c.863G〉T （p. Arg288Met） mutation was found in two cases by sequencing the SMN1 clones, which confirmed that both cases were SMA compound heterozygotes. One case showed partial conversion to form hybrid SMN （SMN2 17/SMN1 E8） identified by clones sequencing and another case carrying 3 SMN2 implied complete conversion from SMN1 to SMN2.Conclusion p. Arg288Met is more a disease-causing mutation than a polymorphism variation, and children with this mutation may have more severe phenotypes.

Novel compound heterozygous GPR56 gene mutation in a twin with lissencephaly:A case report

BACKGROUND Lissencephaly(LIS)is a malformation of cortical development with broad gyri,shallow sulci and thickened cortex characterized by developmental delays and seizures.Currently,20 genes have been implicated in LIS.However,GRP56-related LIS has never been reported.GRP56 is considered one of the causative genes for bilateral frontoparietal polymicrogyria.Here,we report a twin infant with LIS and review the relevant literature.The twins both carried the novel compound heterozygous GPR56 mutations.CASE SUMMARY A 5-mo-old female infant was hospitalized due to repeated convulsions for 1 d.The patient had a flat head deformity that manifested as developmental delays and a sudden onset of generalized tonic-clonic seizures at 5 mo without any causes.The electroencephalography was normal.Brain magnetic resonance imaging revealed a simple brain structure with widened and thickened gyri and shallow sulci.The white matter of the brain was significantly reduced.Patchy long T1 and T2 signals could be seen around the ventricles,which were expanded,and the extracerebral space was widened.Genetic testing confirmed that the patient carried the GPR56 gene compound heterozygous mutations c.228delC(p.F76fs)and c.1820_1821delAT(p.H607fs).The unaffected father carried a heterozygous c.1820_1821delAT mutation,and the unaffected mother carried a heterozygous c.228delC mutation.The twin sister carried the same mutations as the proband.The patient was diagnosed with LIS.CONCLUSION This is the first case report of LIS that is likely caused by mutations of the GPR56 gene.

First cases of MPV17 related mitochondrial DNA depletion syndrome with compound heterozygous mutations in p.R50Q/p.R50W:a case report

Mutations in MPV17 lead to severe mitochondrial DNA depletion syndrome(MTDPS).All known p.R50W variants in MPV17 are lethal.The homozygous variant p.R50Q in MPV17 among patients with Navajo neurohepatopathy is known to allow longer survival,although heterozygous variants p.R50Q have not been reported.This is the first clinical report in compound heterozygosity MPV17 mutation(p.R50W/p.R50Q).Three siblings were admitted due to multiple hepatic nodules;none presented neurological abnormalities.However,they suffered from severe hypoglycemia and cyclic vomiting.The diagnosis of MPV17-related MTDPS was confirmed by detection of a compound heterozygous MPV17 mutation(p.R50W/p.R50Q),and striking reduction of hepatic mitochondrial DNA.One patient developed pediatric-onset of hepatocellular carcinoma.Notably,all patients survived for extended periods,including two patients who received liver transplantation,which contrasted the high mortality rate associated with p.R50W mutations,as previously reported.The p.R50Q mutation might be associated with longer survival and improved liver transplantation outcomes.

Crumbs homolog 2 mutation in two siblings with steroid-resistant nephrotic syndrome:Two case reports

BACKGROUND Crumbs homolog 2(CRB2)is a recently discovered gene that is closely related to the maintenance of normal polarity in podocytes;mutations can directly lead to steroid-resistant nephrotic syndrome(SRNS).However,the characteristics of nephrotic syndrome(NS)caused by CRB2 mutations have not been described.CASE SUMMARY We report a novel compound heterozygous mutation of the CRB2 gene in two siblings with SRNS.The two siblings had edema,proteinuria,hypoproteinemia and hyperlipidemia.Both their father and mother had normal phenotypes(no history of NS).Whole exon sequencing(WES)of the family showed a novel compound heterozygous mutation,c.2290(exon 8)C>T and c.3613(exon 12)G>A.Glucocorticoid therapy(methylprednisolone pulse therapy or oral prednisone)and immunosuppressive agents(tacrolimus)had no effect.During a 3-year follow-up after genetic diagnosis by WES,proteinuria persisted,but the patient was healthy.CONCLUSION CRB2 mutations related to SRNS often occur in exons 7,10,and 12.Clinical manifestations of SRNS caused by CRB2 mutations are often less severe than in other forms of SRNS.

Two novel mutations in the VPS33B gene in a Chinese patient with arthrogryposis,renal dysfunction and cholestasis syndrome 1:A case report

BACKGROUND The VPS33B(OMIM:608552)gene is located on chromosome 15q26.1.We found a female infant with autosomal recessive arthrogryposis,renal dysfunction and cholestasis syndrome 1(ARCS1)caused by mutation in VPS33B.The child was diagnosed with ARCS1(OMIM:208085)after the whole exome sequencing revealed two heterozygous mutations(c.96+1G>C,c.242delT)in the VPS33B gene.CASE SUMMARY We report a Chinese female infant with neonatal cholestasis disorder,who was eventually diagnosed with ARCS1 by genetic analysis.Genetic testing revealed two new mutations(c.96+1G>C and c.242delT)in VPS33B,which is the causal gene.The patient was compound heterozygous,and her parents were both heterozygous.CONCLUSION This study extends the mutational spectrum of the VPS33B gene to provide a molecular basis for the etiological diagnosis of ARCS1 and for genetic counseling of the family.

Autosomal recessive spinocerebellar ataxia type 4 with a VPS13D mutation:A case report

BACKGROUND Autosomal recessive spinocerebellar ataxia type 4(SCAR4)is a type of SCA that is a group of hereditary diseases characterized by gait ataxia.The main clinical features of SCAR4 are progressive cerebellar ataxia,pyramidal signs,neuropathy,and macrosaccadic intrusions.To date,many gene dysfunctions have been reported to be associated with SCAR4.CASE SUMMARY Here,we report a novel compound heterozygous mutation,c.3288delA(p.Asp1097-ThrfsTer6),in the VPS13D gene in a young female Chinese patient.The patient found something wrong with her legs about 10 years ago and presented with the typical characteristics of SCAR4 when she came to the hospital,including ataxia,neuropathy,and positive pyramidal signs.She was then diagnosed with SCAR4 and went home with symptomatic schemes.CONCLUSION SCAR4 is a hereditary disease characterized by ataxia,pyramidal signs,neuropathy,and macrosaccadic intrusions.We report a novel compound heterozygous mutation,c.3288delA(p.Asp1097ThrfsTer6),in the VPS13D gene,which enriches the gene mutation spectrum and provides additional information about SCAR4.

Pseudoileus caused by primary visceral myopathy in a Han Chinese patient with a rare MYH11 mutation:A case report

BACKGROUND Chronic intestinal pseudo-obstruction(CIPO)is a syndrome of intestinal motor dysfunction caused by intestinal nerve,muscle,and/or Cajal stromal cell lesions.CIPO is a serious category of gastrointestinal dynamic dysfunction,which can eventually lead to the death of patients with intestinal failure.Due to considerable phenotypic heterogeneity,the estimated incidence of CIPO is 1/476190 and 1/416666 in men and women,respectively.According to the etiology,CIPO can be divided into idiopathic and secondary,of which the latter is the most common,often secondary to tumor,virus infection,connective tissue disease,neurological diseases,and endocrine diseases.Idiopathic CIPO in the intestinal tract is divided into visceral myopathy,neuropathy,and stromal cell lesions according to the location.Surgery is usually not recommended for CIPO,because it often does not benefit patients with CIPO,and postoperative intestinal obstruction is likely to occur,which may even worsen the condition.CASE SUMMARY Here,we describe the case of a 43-year-old male Han Chinese patient with a 15-year history of recurrent abdominal distention with no clear cause.The results of physical,biochemical,and other relevant examinations showed no clear abnormalities.Contrast-enhanced computed tomography(CT)indicated a large duodenum,clear expansion of the intestinal lumen,and CIPO.Whole exome sequencing(WES)of the patient and his mother confirmed the diagnosis of primary familial visceral myopathy type 2 chronic pseudoileus with a rare heterozygous gene mutation in MYH11.This is the second reported case of CIPO with a heterozygous MYH11[NM_001040113.1:c.5819delC(p.Pro1940Hisfs*91)]mutation.CONCLUSION This case report indicates that physicians can perform routine clinical examinations,CT,and WES to achieve a diagnosis and treatment of CIPO in early disease stages.

Mutation detection of type Ⅱ hair cortex keratin gene KRT86 in a Chinese Han family with congenital monilethrix

Background Monilethrix is an autosomal dominant hair disorder characterized clinically by alopecia and follicular papules.In this study,we collected a Han monilethrix family to detect the mutations in patients and investigated the correlation between the genotype and phenotype of monilethrix.Methods In this study,we identified a Chinese family with monilethrix through light microscopic and scanning electron microscopic （SEM） examination.Genomic DNA from peripheral blood samples was prepared.DNA samples from controls and monilethrix patients were subject to polymerase chain reaction （PCR） amplification.Two pairs of primers were used to amplify the seventh exon of KRT86.Mutation screening of the PCR products was detected using direct sequencing.Results Light microscopic examination showed a regular alternate enlargement and narrow area.SEM examination showed that part of the cuticle of the nodules shed and disappeared gradually in the narrow area with granular protrusions on the surface similar to the erosion-like structure.Parallel longitudinal ridge and groovepattern appeared,and the ridges varied in width,like dead wood.A heterozygous transversion mutation c.1204G＞A（p.E402K） in the seventh exon of KRT86 was identified in both patients.Conclusions The mutation of extron 7 of KRT86 identified plays a major role in the pathogenesis of this pedigree with monilethrix,and is a mutation hot spot of KRT86.Further research is needed to explore the relationship between the phenotype and the mutation of the type Ⅱ hair keratin gene KRT86 of monilethrix.

A HRG novel mutation associated with idiopathic portal hypertension: Case report and literature review

Idiopathic portal hypertension(IPH)is defined as the presence of portal hypertension in the absence of a common cause.IPH can have several etiologies,one of which is a genetic disorder.Some genetic mutations,such as KCNN3 and DGUOK,were shown to be related to IPH pathogenesis.This is the first case report of a 22-year-old man who was diagnosed with IPH with a novel heterozygous mutation in the histidine-rich glycoprotein gene(c.545G>C,p.R182T).Using bioinformatics analysis and the protein quantification method,we showed that this novel mutation has a pathogenetic role in IPH.Our study broadens the mutation spectrum of the histidine-rich glycoprotein gene and provides new ideas for IPH etiology.

HTRA1-related autosomal dominant cerebral small vessel disease

Background:Homozygous or compound heterozygous mutations in high temperature requirement serine peptidase A1(HTRA1)gene are responsible for cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy(CARASIL).Recently,increasing evidence has shown that heterozygous HTRA1 mutations are also associated with cerebral small vessel disease(CSVD)with an autosomal dominant pattern of inheritance.This study was aimed to analyze the genetic and clinical characteristics of HTRA1-related autosomal dominant CSVD.Methods:We presented three new Chinese cases of familial CSVD with heterozygous HTRA1 mutations and reviewed all clinical case reports and articles on HTRA1-related autosomal dominant CSVD included in PUBMED by the end of March 1,2020.CARASIL probands with genetic diagnosis reported to date were also reviewed.The genetic and clinical characteristics of HTRA1-related autosomal dominant CSVD were summarized and analyzed by comparing with CARASIL.Results:Forty-four HTRA1-related autosomal dominant CSVD probands and 22 CARASIL probands were included.Compared with typical CARASIL,HTRA1-related autosomal dominant probands has a higher proportion of vascular risk factors(P<0.001),a later onset age(P<0.001),and a relatively slower clinical progression.Alopecia and spondylosis can be observed,but less than those in the typical CARASIL.Thirty-five heterozygous mutations in HTRA1 were reported,most of which were missense mutations.Amino acids located close to amino acids 250-300 were most frequently affected,followed by these located near 150∼200.While amino acids 250∼300 were also the most frequently affected region in CARASIL patients,fewer mutations precede the 200th amino acids were detected,especially in the Kazal-type serine protease domain.Conclusions:HTRA1-related autosomal dominant CSVD is present as a mild phenotype of CARASIL.The trend of regional concentration of mutation sites may be related to the concentration of key sites in these regions which are responsible for pathogenesis of HTRA1-related autosomal dominant CSVD.