BACKGROUND Pulmonary hypertension (PH) causes significant morbidity and mortality in diverse childhood diseases.However,limited information has been reported to obtain a good understanding of pediatric PH.Gaps exist b...BACKGROUND Pulmonary hypertension (PH) causes significant morbidity and mortality in diverse childhood diseases.However,limited information has been reported to obtain a good understanding of pediatric PH.Gaps exist between genome sequencing and metabolic assessments and lead to misinterpretations of the complicated symptoms of PH.Here,we report a rare case of a patient who presented with severe PH as the first manifestation without significant cardiovascular malformation and was finally diagnosed with methylmalonic aciduria (MMA) after metabolic and genomic assessments.CASE SUMMARY An 11-year-old female presented with an aggressive reduction in activity capability and shortness of breath for only 4 mo and suffered from unexplained PH.A series of examinations was performed to evaluate any possible malformations or abnormalities of the cardiovascular system and lungs,but negative results were obtained.The blood tests were normal except for manifestations of microcytic anemia and elevated total homocysteine.Computed tomography and magnetic resonance imaging failed to identify any pulmonary diseases.Cardiac catheterization examination identified a small right coronary artery to pulmonary artery shunt and severe PH.During the follow-up,PH progressed rapidly.Then,genome sequencing and metabolic disorder screening were performed,which confirmed a diagnosis of MMA with MMACHC c.80A>G/c and 609G> A mutations.Vitamin B12,betaine and bosentan were then administered as the main treatments.During the 6-mo follow-up,the pulmonary artery pressure dropped to 45 mmHg,while the right ventricle structure recovered.The patient’s heart function recovered to NYHA class Ⅱ.Metabolic disorder analysis failed to identify significant abnormalities.CONCLUSION As emerging types of metabolic dysfunction have been shown to present as the first manifestation of PH,and taking advantage of next generation sequencing technology,genome sequencing and metabolic disorder screening are recommended to have a more superior role when attempting to understand unclear or aggressive PH.展开更多
Methylmalonic aciduria （MMA） is an autosomal recessive disorder of cobalamin （cbl） metabolism. Cobalamin C （cblC） disease is the most common type of MMA and is characteristically concurrent with homocystinemia ...Methylmalonic aciduria （MMA） is an autosomal recessive disorder of cobalamin （cbl） metabolism. Cobalamin C （cblC） disease is the most common type of MMA and is characteristically concurrent with homocystinemia （HCY） due to impaired synthesis of two active forms of cbl, namely adenosylcobalamin （AdoCbl） and methylcobalamin （MeCbl）. The estimated worldwide incidence of MMA ranges between 1：48,000 and 1：250,000. Mutations of the MMA and HCY type C protein （MMACtfC） gene are responsible for cblC disease and were first identified by Lerner-Ellis et aL in 2006.By the year 2016, more than 82 different MMACHC gene mutations have been reported （http：// www.hgmd.cf.ac.uk/ac/index.php）. Among these mutations, c.609G〉A （p.W203X） was reported to be the most frequent cblC mutation in Chinese patients.展开更多
Background: This study aims to study MUT gene mutation spectrum in Chinese patients with isolated methylmalonic academia (MMA) and their clinical features for the potential genotype-phenotype correlation. Methods: For...Background: This study aims to study MUT gene mutation spectrum in Chinese patients with isolated methylmalonic academia (MMA) and their clinical features for the potential genotype-phenotype correlation. Methods: Forty-three patients were diagnosed with isolated MMA by elevated blood propionylcarnitine, propionylcarnitine to acetylcarnitine ratio, and urine methylmalonate without hyperhomocysteinemia. The MUT gene was amplifi ed by polymerase chain reaction and directly sequenced. Those patients with at least one variant allele were included. The novel missense mutations were assessed by bioinformatic analysis and screened against alleles sequenced from 50 control participants. Results: Among the 43 patients, 38 had typical clinical presentations, and the majority (30/38) experienced early-onset MMA. Eight patients died and seven were lost to follow-up. Twenty patients had poor outcomes and eight showed normal development. The 43 identified MUT gene mutations had at least one variant allele, whereas 35 had two mutant alleles. Of the 33 mutations reported before, eight recurrent mutations were identified in 32 patients, and c.729_730insTT (p.D244Lfs*39) was the most common (12/78) in the mutant alleles. Of the 10 novel mutations, six were missense mutations and four were premature termination codon mutations. The six novel missense mutations seemed to be pathogenic. Conclusions: A total of 10 novelMUT mutations were detected in the Chinese population. c.729_730insTT (p.D244Lfs*39) was the most frequent mutation. A genotype-phenotype correlation could not be found, but the genotypic characterization indicated the need of genetic counseling for MMA patients and early prenatal diagnoses for high-risk families.展开更多
Background Methylmalonic acidemia （MMA） is a multifactorial autosomal recessive inborn error of organic acid metabolism, often presenting with neurological symptoms. As neurological disorders are often related to wh...Background Methylmalonic acidemia （MMA） is a multifactorial autosomal recessive inborn error of organic acid metabolism, often presenting with neurological symptoms. As neurological disorders are often related to white matter injury, diffusion tensor imaging （DTI） is an excellent tool for assessment of white matter injury and possibly for diagnosing this disorder. Methods We retrospectively analyzed DTI images of 12 patients with MMA （7 males, 5 females, age range： 7-12 months, mean age： 9.25±1.70 months） with negative MRI findings. And another 12 age-matched and gender-matched infants were enrolled as control subjects. Fractional anisotropy （FA） of different white matter tracts of the brain was measured in both groups. Results For patients with negative MRI findings, compared with healthy infants, a statistically significant reduction in DTI FA value of the frontal white matter, temporal white matter, and occipital white matter was observed （P〈0.01）. Conclusions In addition to conventional TlW and T2W MR Image, Brain DTI presents a useful, sensitive and complementary tool for the assessment of brain damage in patients with MMA.展开更多
Background:There are few detailed consensus and guidelines on perioperative clinical characteristicsof liver transplantation(LT)in patients with methylmalonic acidemia(MMA).This retrospective studyinvestigated details...Background:There are few detailed consensus and guidelines on perioperative clinical characteristicsof liver transplantation(LT)in patients with methylmalonic acidemia(MMA).This retrospective studyinvestigated details of the clinical course and individualized treatment plan of the center with largestexperience in China.Methods:A total of 7 MMA patients undergoing LT in Beijing Friendship Hospital from June 2013 toDecember 2017 were enrolled in the study,whose clinical data(clinical characteristics,laboratory findings,chronological changes in urine MMA levels,treatment,etc.)during perioperative period were analyzedretrospectively.All the patients received strict postoperative management.Results:All the 7 cases were confirmed to have isolated MMA,among which,3 cases received livingdonor liver transplantation(LDLT),4 cases received deceased donor liver transplantation(DDLT).A wildfluctuate of metabolic condition was observed within the first few days after surgery and two weeks afterLT,the mean base excess of blood value(BE-B)restored to normal whereas plasma bicarbonate(HCO3-)was still below normal value even with intermittent sodium bicarbonate correction.It also showed markedreduction in propionylcarnitine(C3)and C3/C2 level and the mean urine MMA by gas chromatographymassspectrometry(GC-MS)was reduced by 81.7%(P<0.01)but remained>72×higher than upper limitof normal.The metabolism-correcting medications were administered as before.The renal function ofone case with renal insufficiency before LT(serum creatinine rising)maintained stable by adjusting theimmunosuppressive regimen during the observation period.All patients survive to date.Conclusions:LT is an effective treatment to prevent metabolic crisis,but patients with MMA tend to bemetabolically fragile even after surgery.During perioperative period,close monitoring should be given foracidosis episodes so as to implement sodium bicarbonate correction.Metabolism-correcting medications arestill needed.Special immunosuppressive regimen is an effective way of maintaining renal function for thosewith kidney dysfunction.展开更多
文摘BACKGROUND Pulmonary hypertension (PH) causes significant morbidity and mortality in diverse childhood diseases.However,limited information has been reported to obtain a good understanding of pediatric PH.Gaps exist between genome sequencing and metabolic assessments and lead to misinterpretations of the complicated symptoms of PH.Here,we report a rare case of a patient who presented with severe PH as the first manifestation without significant cardiovascular malformation and was finally diagnosed with methylmalonic aciduria (MMA) after metabolic and genomic assessments.CASE SUMMARY An 11-year-old female presented with an aggressive reduction in activity capability and shortness of breath for only 4 mo and suffered from unexplained PH.A series of examinations was performed to evaluate any possible malformations or abnormalities of the cardiovascular system and lungs,but negative results were obtained.The blood tests were normal except for manifestations of microcytic anemia and elevated total homocysteine.Computed tomography and magnetic resonance imaging failed to identify any pulmonary diseases.Cardiac catheterization examination identified a small right coronary artery to pulmonary artery shunt and severe PH.During the follow-up,PH progressed rapidly.Then,genome sequencing and metabolic disorder screening were performed,which confirmed a diagnosis of MMA with MMACHC c.80A>G/c and 609G> A mutations.Vitamin B12,betaine and bosentan were then administered as the main treatments.During the 6-mo follow-up,the pulmonary artery pressure dropped to 45 mmHg,while the right ventricle structure recovered.The patient’s heart function recovered to NYHA class Ⅱ.Metabolic disorder analysis failed to identify significant abnormalities.CONCLUSION As emerging types of metabolic dysfunction have been shown to present as the first manifestation of PH,and taking advantage of next generation sequencing technology,genome sequencing and metabolic disorder screening are recommended to have a more superior role when attempting to understand unclear or aggressive PH.
文摘Methylmalonic aciduria （MMA） is an autosomal recessive disorder of cobalamin （cbl） metabolism. Cobalamin C （cblC） disease is the most common type of MMA and is characteristically concurrent with homocystinemia （HCY） due to impaired synthesis of two active forms of cbl, namely adenosylcobalamin （AdoCbl） and methylcobalamin （MeCbl）. The estimated worldwide incidence of MMA ranges between 1：48,000 and 1：250,000. Mutations of the MMA and HCY type C protein （MMACtfC） gene are responsible for cblC disease and were first identified by Lerner-Ellis et aL in 2006.By the year 2016, more than 82 different MMACHC gene mutations have been reported （http：// www.hgmd.cf.ac.uk/ac/index.php）. Among these mutations, c.609G〉A （p.W203X） was reported to be the most frequent cblC mutation in Chinese patients.
基金supported by grants from the National Key Technology R&D Program(2012BAI09B04)the Special Basic Work of Science and Technology(2014FY110700).
文摘Background: This study aims to study MUT gene mutation spectrum in Chinese patients with isolated methylmalonic academia (MMA) and their clinical features for the potential genotype-phenotype correlation. Methods: Forty-three patients were diagnosed with isolated MMA by elevated blood propionylcarnitine, propionylcarnitine to acetylcarnitine ratio, and urine methylmalonate without hyperhomocysteinemia. The MUT gene was amplifi ed by polymerase chain reaction and directly sequenced. Those patients with at least one variant allele were included. The novel missense mutations were assessed by bioinformatic analysis and screened against alleles sequenced from 50 control participants. Results: Among the 43 patients, 38 had typical clinical presentations, and the majority (30/38) experienced early-onset MMA. Eight patients died and seven were lost to follow-up. Twenty patients had poor outcomes and eight showed normal development. The 43 identified MUT gene mutations had at least one variant allele, whereas 35 had two mutant alleles. Of the 33 mutations reported before, eight recurrent mutations were identified in 32 patients, and c.729_730insTT (p.D244Lfs*39) was the most common (12/78) in the mutant alleles. Of the 10 novel mutations, six were missense mutations and four were premature termination codon mutations. The six novel missense mutations seemed to be pathogenic. Conclusions: A total of 10 novelMUT mutations were detected in the Chinese population. c.729_730insTT (p.D244Lfs*39) was the most frequent mutation. A genotype-phenotype correlation could not be found, but the genotypic characterization indicated the need of genetic counseling for MMA patients and early prenatal diagnoses for high-risk families.
基金This work was supported by National Science Foundation of China （No. 50537030）.
文摘Background Methylmalonic acidemia （MMA） is a multifactorial autosomal recessive inborn error of organic acid metabolism, often presenting with neurological symptoms. As neurological disorders are often related to white matter injury, diffusion tensor imaging （DTI） is an excellent tool for assessment of white matter injury and possibly for diagnosing this disorder. Methods We retrospectively analyzed DTI images of 12 patients with MMA （7 males, 5 females, age range： 7-12 months, mean age： 9.25±1.70 months） with negative MRI findings. And another 12 age-matched and gender-matched infants were enrolled as control subjects. Fractional anisotropy （FA） of different white matter tracts of the brain was measured in both groups. Results For patients with negative MRI findings, compared with healthy infants, a statistically significant reduction in DTI FA value of the frontal white matter, temporal white matter, and occipital white matter was observed （P〈0.01）. Conclusions In addition to conventional TlW and T2W MR Image, Brain DTI presents a useful, sensitive and complementary tool for the assessment of brain damage in patients with MMA.
基金This work was supported by The Capital Health Research and Development of Special(No.2016-1-2021)and Beijing Municipal Administration of Hospitals Ascent Plan(Code:DFL20150101).
文摘Background:There are few detailed consensus and guidelines on perioperative clinical characteristicsof liver transplantation(LT)in patients with methylmalonic acidemia(MMA).This retrospective studyinvestigated details of the clinical course and individualized treatment plan of the center with largestexperience in China.Methods:A total of 7 MMA patients undergoing LT in Beijing Friendship Hospital from June 2013 toDecember 2017 were enrolled in the study,whose clinical data(clinical characteristics,laboratory findings,chronological changes in urine MMA levels,treatment,etc.)during perioperative period were analyzedretrospectively.All the patients received strict postoperative management.Results:All the 7 cases were confirmed to have isolated MMA,among which,3 cases received livingdonor liver transplantation(LDLT),4 cases received deceased donor liver transplantation(DDLT).A wildfluctuate of metabolic condition was observed within the first few days after surgery and two weeks afterLT,the mean base excess of blood value(BE-B)restored to normal whereas plasma bicarbonate(HCO3-)was still below normal value even with intermittent sodium bicarbonate correction.It also showed markedreduction in propionylcarnitine(C3)and C3/C2 level and the mean urine MMA by gas chromatographymassspectrometry(GC-MS)was reduced by 81.7%(P<0.01)but remained>72×higher than upper limitof normal.The metabolism-correcting medications were administered as before.The renal function ofone case with renal insufficiency before LT(serum creatinine rising)maintained stable by adjusting theimmunosuppressive regimen during the observation period.All patients survive to date.Conclusions:LT is an effective treatment to prevent metabolic crisis,but patients with MMA tend to bemetabolically fragile even after surgery.During perioperative period,close monitoring should be given foracidosis episodes so as to implement sodium bicarbonate correction.Metabolism-correcting medications arestill needed.Special immunosuppressive regimen is an effective way of maintaining renal function for thosewith kidney dysfunction.
