Case 1: A 19-day-old male infant presented with poor feeding and decreased activity for 2 weeks, worsening with poor responsiveness for 3 days. At 5 days old, he developed poor feeding and poor responsiveness, was hospitalized, and was found to have elevated blood ammonia and thrombocytopenia. Whole-genome genetic analysis revealed a pathogenic homozygous mutation in the PCCA gene, NM-000282.4: c.1834-1835del (p.Arg612AspfsTer44), leading to a diagnosis of propionic acidemia. Case 2: A 4-day-old male infant presented with poor responsiveness and feeding difficulties since birth, with elevated blood ammonia for 1 day. He showed weak sucking and deteriorating responsiveness, with blood ammonia >200 µmol/L. Genetic testing identified two heterozygous mutations in the MMUT gene: NM_000255.4: c.1677-1G>A and NM_000255.4: ex.5del, confirming methylmalonic acidemia. Case 3: A 20-day-old male infant presented with poor feeding for 15 days and skin petechiae for 8 days. He developed feeding difficulties at 5 days old and lower limb petechiae at 12 days old, with blood ammonia measured at 551.6 µmol/L. Genetic analysis found two heterozygous mutations in the PCCA gene: NM_000282.4: c.1118T>A (p.Met373Lys) and NM_000282.4: ex.16-18del, confirming propionic acidemia. In the first two cases, continuous hemodiafiltration was performed for 30 hours and 20 hours, respectively, before administering carglumic acid. In the third case, carglumic acid was administered orally without continuous hemodiafiltration, resulting in a decrease in blood ammonia from 551.6 µmol/L to 72.0 µmol/L within 6 hours, with a reduction rate of approximately 20-25 µmol/(kg·h), similar to the first two cases. Carglumic acid was effective in all three cases, suggesting it may help optimize future treatment protocols for organic acidemia.
Humans ; Male ; Infant, Newborn ; Propionic Acidemia/drug therapy* ; Amino Acid Metabolism, Inborn Errors/genetics* ; Mutation ; Methylmalonyl-CoA Decarboxylase/genetics* ; Citrates/administration & dosage* ; Carbon-Carbon Ligases/genetics* ; Glutamates

Humans ; Propionic Acidemia/complications* ; Cardiomyopathy, Dilated/etiology*

Methylmalonic acidemia (MMA) is a series of rare inherited organic acid metabolic disorders with variable and nonspecific clinical manifestations, in particular neurological symptoms such as vomiting, lethargy, etc. Even with timely treatment, patients may still have various degrees of neurological complications and can even die. The prognosis is mainly related to the type of genetic variants, level of metabolites, newborn screening, onset of disease and early initiation of treatment. This article has reviewed the prognosis of patients with various types of MMA and factors that may affect it.
Infant, Newborn ; Humans ; Amino Acid Metabolism, Inborn Errors/complications* ; Prognosis ; Mutation ; Neonatal Screening ; Propionic Acidemia

Objective: Propionic acidemia is a rare inherited metabolic disorder caused by propionyl CoA carboxylase (PCC) deficiency. This study aims to analyze the clinical characteristics and gene variations of Chinese patients with propionic acidemia, and to explore the correlation between clinical phenotypes and genotypes. Methods: Single-center, retrospective and observational study. Seventy-eight patients of propionic acidemia (46 males and 32 females) from 20 provinces and autonomous regions were admitted from January 2007 to April 2022. Their age of initial diagnosis ranged from 7 days to 15 years. The clinical manifestations, biochemical and metabolic abnormalities, genetic variations, diagnosis, treatment and outcome were studied. Chi-Square test or Mann-Whitney U test were used for statistical analysis. Results: Among 78 cases, 6 (7.7%) were identified by newborn screening; 72 (92.3%) were clinically diagnosed after onset, and the age of onset was 2 hours after birth to 15 years old; 32 cases had early-onset disease and 40 cases had late-onset disease. The initial manifestations included lethargy, hypotonia, vomiting, feeding difficulties, developmental delay, epilepsy, and coma. Among the 74 cases who accepted gene analysis, 35 (47.3%) had PCCA variants and 39 (52.7%) had PCCB variants. A total of 39 PCCA variants and 32 PCCB variants were detected, among which c.2002G>A and c.229C>T in PCCA and c.838dupC and c.1087T>C in PCCB were the most common variants in this cohort. The variants c.1228C>T and c.1283C>T in PCCB may be related to early-onset type. The variants c.838dupC, c.1127G>T and c.1316A>G in PCCB, and c.2002G>A in PCCA may be related to late-onset disease. Six patients detected by newborn screening and treated at asymptomatic stage developed normal. The clinically diagnosed 72 cases had varied complications. 10 (12.8%) cases of them died. 62 patients improved after metabolic therapy by L-carnitine and diet. Six patients received liver transplantation because of recurrent metabolic crisis. Their clinical symptoms were markedly improved. Conclusion: The clinical manifestations of propionic acidemia are complex and lack of specificity. Newborn screening and high-risk screening are keys for early treatment and better outcome. The correlation between the genotype and phenotype of propionic acidemia is unclear, but certain variants may be associated with early-onset or late-onset propionic acidemia.
Carnitine ; Female ; Genotype ; Humans ; Male ; Methylmalonyl-CoA Decarboxylase/metabolism* ; Mutation ; Phenotype ; Propionic Acidemia/genetics* ; Retrospective Studies

OBJECTIVE: To detect pathogenic variants in a pedigree affected with propionic acidemia (PA). METHODS: The proband was subjected to high-throughput next-generation sequencing. Suspected variants were validated by Sanger sequencing of his family members. mRNA was extracted from peripheral blood lymphocytes from the proband's father in order to verify the impact of the splicing variant by RT-PCR combined with Sanger sequencing. The pathogenicity of the missense variant was predicted by using PolyPhen-2, Mutation Taster, SIFT, COBALT and HOPE software. RESULTS: The proband was found to harbor compound heterozygous variants of the PCCB gene, namely c.184-2A>G and c.733G>A (p.G245S), which were respectively inherited from his father and mother. RT-PCR combined with Sanger sequencing confirmed skipping of exon 2 during transcription. Bioinformatic analysis indicated the c.733G>A (p.G245S) variant to be damaging. CONCLUSION The two variants of the PCCB gene probably underlay the disease in this patient. Above findings have enriched the spectrum of PCCB gene variants.
Exons ; Humans ; Mutation ; Mutation, Missense ; Pedigree ; Propionic Acidemia/genetics*

Propionic acidemia (PA) is a rare organic acidemia resulting from a deficiency of the mitochondrial enzyme propionyl-coenzyme A carboxylase. Most cases are diagnosed after the detection of metabolic abnormalities—such as hyperammonemia, metabolic acidosis, and ketosis—associated with complaints of vomiting, feeding difficulties, and hypotonia during the neonatal period. However, in rare late-onset cases, mild or vague symptoms make the diagnosis more challenging. Even though acute pancreatitis is relatively uncommon in children, it can occur in association with PA. We present the case of a 4-year-old child who was admitted owing to the complaint of recurrent pancreatitis and had not previously been diagnosed with having metabolic disease. During inpatient treatment for acute pancreatitis, convulsions occurred with concomitant hyperammonemia, metabolic acidosis, coagulopathy, and shock 1 week after the administration of total parenteral nutrition. He was diagnosed to have PA after a metabolic work-up and confirmed to have novel mutation by molecular genetic analysis. Because children with PA may have acute pancreatitis, although rare, vomiting and abdominal pain should raise a suspicion of acute pancreatitis. On the contrary, even among children who have never been diagnosed with a metabolic disease, if a child has recurrent pancreatitis, metabolic pancreatitis caused by organic acidemia should be considered.]]>
Abdominal Pain ; Acidosis ; Child ; Child, Preschool ; Diagnosis ; Diethylpropion ; Humans ; Hyperammonemia ; Inpatients ; Metabolic Diseases ; Methylmalonyl-CoA Decarboxylase ; Molecular Biology ; Muscle Hypotonia ; Pancreatitis ; Parenteral Nutrition, Total ; Propionic Acidemia ; Seizures ; Shock ; Vomiting

OBJECTIVETo analyze PCCA and PCCB gene mutations in 10 Chinese patients with propionic acidemia(PA).

METHODSGenomic DNA was extracted from peripheral blood leukocytes. The 39 exons and flanking sequences of the PCCA and PCCB genes were amplified with polymerase chain reaction and subjected to direct DNA sequencing.

RESULTSDNA sequencing has revealed that 7 patients have carried a PCCA gene mutation, 2 patients carried PCCB gene mutation and 1 patient carried mutations in both PCCA and PCCB genes. Ten PA mutations were confirmed, including 8 affecting the PCCA gene and 2 affecting the PCCB gene. Three PCCA mutations c.245G>A, IVS15+5del5, c.1288C>T and 2 PCCB mutations c.838insC, c.1087T>C were found for the first time.

CONCLUSIONAmong Chinese patients with propionic acidemia patients, their genetic mutations are mainly found on the PCCA gene.

Child, Preschool ; Female ; Humans ; Infant ; Male ; Methylmalonyl-CoA Decarboxylase ; genetics ; Mutation ; Propionic Acidemia ; genetics

Propionic acidemia (PA) is a rare autosomal recessive disorder of metabolism caused by deficient activity of the mitochondrial enzyme propionyl-CoA carboxylase. The clinical manifestations are metabolic acidosis, poor feeding, lethargy, vomiting, osteoporosis, neurological dysfunction, pancytopenia, developmental retardation and cardiomyopathy. Liver transplantation has recently been considered as one of the treatment options for patients with PA. This case report describes several anesthetic considerations for patients with PA undergoing liver transplantation. Understanding the patient's status and avoiding events that may precipitate metabolic acidosis are important for anesthetic management of patients with PA. In conclusion, anesthesia should be focused on minimizing the severity of metabolic acidosis with following considerations: (1) maintaining optimal tissue perfusion by avoiding hypotension, (2) preventing hypoglycemia, and (3) providing bicarbonate to compensate for the acidosis.
Acidosis ; Acyl Coenzyme A ; Anesthesia ; Cardiomyopathies ; Child ; Diethylpropion ; Humans ; Hypoglycemia ; Hypotension ; Lethargy ; Liver ; Liver Transplantation ; Methylmalonyl-CoA Decarboxylase ; Osteoporosis ; Pancytopenia ; Perfusion ; Propionic Acidemia ; Vomiting

OBJECTIVETo study the clinical features of organic acidemia in neonates admitted to the intensive care unit.

METHODSThe clinical features of neonates from 15 neonatal intensive care units of Henan Province, who were diagnosed with congenital organic acidemia by gaschromatography-mass spectrometry (GC-MS) between June 2008 and August 2011 were retrospectively reviewed.

RESULTSFifty neonates of 287 high risk neonates were confirmed as having or highly suspected to have inborn errors of metabolism. Of the 50 cases, 32 cases were diagnosed with organic acidemia disease, including 28 cases of methylmalonic acidemia, 2 cases of propionic acidemia, 1 case of maple syrup urine disease and 1 case of isovaleric acldemla. In most cases, disease onset occurred in the first week after birth in most of cases (75%). Neonates whose symptoms occurred immediately after or within a few hours of birth presented with serious conditions. Clinical manifestations were various and mainly related to neurologic, respiratory and gastrointestinal symptoms such as poor response, coma, drowsiness, abnormal muscle tone, convulsions, polypnea, dyspnea, milk refusal, diarrhea and jaundice. Initial symptoms were non-specific and included dyspnea, poor response, milk refusal, lethargy and seizures.

CONCLUSIONSMethylmalonic acidemia is a common inherited metabolic disease in the neonatal period. Clinical manifestations of organic acid metabolism abnormalities in neonates are atypical and early onset is associated with more serious conditions.

Amino Acid Metabolism, Inborn Errors ; complications ; diagnosis ; Diagnosis, Differential ; Female ; Gas Chromatography-Mass Spectrometry ; Humans ; Infant, Newborn ; Intensive Care Units, Neonatal ; Male ; Maple Syrup Urine Disease ; complications ; diagnosis ; Propionic Acidemia ; complications ; diagnosis

Humans ; Infant ; Male ; Propionic Acidemia ; complications ; diagnosis ; therapy