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

OBJECTIVE: To explore the genetic basis for a child with Isolated sulfite oxidase deficiency (ISOD). METHODS: The child and her parents were subjected to targeted capture and next-generation sequencing. Pathogenicity of candidate variants was assessed based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). RESULTS: The child was found to harbor compound heterozygous variants of the SUOX gene, namely c.1200C>G (p.Tyr400*) and c.1406_1421delCCTGGCAGGTGGCTAA (p.Thr469Serfs*20), which were inherited from her mother and father, respectively. The c.1200C>G was a known pathogenic variant, while the c.1406_1421delCCTGGCAGGTGGCTAA was unreported previously and predicted to be a pathogenic variant (PVS1+PM2_Supporting +PM3) based on the guidelines from the American College of Medical Genetics and Genomics. CONCLUSION The compound c.1200C>G and c.1406_1421delCCTGGCAGGTGGCTAA variants of the SUOX gene probably underlay the pathogenesis of ISOD in this child. Above finding has expanded the spectrum of SUOX gene variants and provided molecular evidence for the clinical diagnosis and genetic counseling for this pedigree.
Child ; Female ; Humans ; Amino Acid Metabolism, Inborn Errors/genetics* ; Genetic Counseling ; Genomics ; High-Throughput Nucleotide Sequencing ; Mutation

OBJECTIVE: To carry out Sanger sequencing for MMACHC gene variants among 65 Chinese pedigrees affected with combined methylmalonic aciduria and homocysteinemia, and summarize their genetic and clinical characteristics and prognosis. METHODS: Clinical characteristics of the 65 children identified with Methylmalonic acidemia and homocysteinemia at the Children's Hospital Affiliated to Zhengzhou University (Zhengzhou Children's Hospital) from April 2017 to April 2022 were selected as the study subjects. Potential variants of the MMACHC gene were detected by direct sequencing of the PCR products. RESULTS: The median age of the 65 children was 3 months (14 days to 17 years old). These included 28 cases (43.08%) from neonatal screening, 11 cases (16.92%) with a history of jaundice, and 9 cases (13.85%) with various degrees of anemia. The main clinical symptoms included development delay, slow growth, epilepsy, hydrocephalus, lethargy, feeding difficulty, regression or decline in motor ability, recurrent respiratory infections, anemia, jaundice, respiratory and heart failures, hydrocephalus, limb weakness, and hypertension. Blood and urine tandem mass spectrometry screening has revealed increase of methylmalonic acid, propionyl carnitine, propionyl carnitine/acetylcarnitine ratio, and propionyl carnitine/free carnitine ratio to various extents, and blood homocysteine was increased in all patients. The detection rate of genetic variants was 98.46% (128/130), and in total 22 types of MMACHC gene variants were detected. The most common ones have included c.609G>A (W203X) (58/128), c.658-660del (K220del) (19/128), and c.80A>G (Q27A) (16/128). Two novel variants have been identified, namely c.565C>T (p.R189C) and c.624_ 625delTG (p.A208Afs), which were respectively predicted as likely pathogenic (PM2_Supporting+PM3+PP2+PP3) and pathogenic (PVS1+PM2_Supporting+PM3+PP2) based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). Exon 4 had the highest frequency for the detection. CONCLUSION Identification of MMACHC gene variants has confirmed the diagnosis in the children, among which the c.609G>A variant has the highest frequency. Discovery of the new variants has enriched the mutational spectrum of the MMACHC gene.
Humans ; Amino Acid Metabolism, Inborn Errors/genetics* ; Hydrocephalus ; Oxidoreductases

OBJECTIVE: To explore the clinical phenotype and genetic features of two children with MEGDEL syndrome due to variants of the SERAC1 gene. METHODS: Two children who had presented at the Fujian Medical University Union Hospital respectively on July 14, 2020 and July 28, 2018 were selected as the study subjects. Clinical features and results of genetic testing were retrospectively analyzed. RESULTS: Both children had featured developmental delay, dystonia and sensorineural deafness, along with increased urine 3-methylglutaric acid levels. Magnetic resonance imaging revealed changes similar to Leigh-like syndrome. Gene sequencing revealed that both children have harbored pathogenic compound heterozygous variants of the SERAC1 gene, including c.1159C>T and c.442C>T in child 1, and c.1168C>T and exons 4~9 deletion in child 2. CONCLUSION Children with MEGDEL syndrome due to SERAC1 gene variants have variable clinical genotypes. Delineation of its clinical characteristics and typical imaging changes can facilitate early diagnosis and treatment. Discovery of the novel variants has also enriched the spectrum of SERAC1 gene variants.
Humans ; Retrospective Studies ; Metabolism, Inborn Errors ; Hearing Loss, Sensorineural/genetics* ; Dystonia ; Carboxylic Ester Hydrolases

OBJECTIVE: To explore the clinical features and genetic basis for a child with 3-methylglutaconic aciduria type VII. METHODS: A child who was diagnosed at the Gansu Provincial Maternity and Child Health Care Hospital on August 9, 2019 was selected as the study subject. Clinical data of the child, including urine gas chromatography and mass spectrometry, were collected. The child and her parents were subjected to whole exome sequencing. RESULTS: The child, a female neonate, had presented mainly with intermittent skin cyanosis, convulsions, hypomagnesemia, apnea, neutropenia after birth. Her urine 3-methylpentenedioic acid has increased to 17.53 μmol/L. DNA sequencing revealed that she has harbored compound heterozygous variants of the CLPB gene, namely c.1016delT (p.L339Rfs*5) and c.1087A>G (p.R363G), which were respectively inherited from her mother and father. Both variants were unreported previously. Based on the standards from the American College of Medical Genetics and Genomics (ACMG), the variants were respectively predicted to be pathogenic and likely pathogenic. CONCLUSION The child was diagnosed with 3-methylglutenedioic aciduria type VII. Discovery of the c.1016delT and c.1087A>G variants has enriched the mutational spectrum of the CLPB gene.
Female ; Humans ; Infant, Newborn ; Pregnancy ; Base Sequence ; Metabolism, Inborn Errors/diagnosis* ; Mutation ; Neutropenia/genetics* ; Sequence Analysis, DNA

OBJECTIVE: To explore the clinical features and genetic variant in a child with Cerebral creatine deficiency syndrome (CCDS). METHODS: A child who had presented at the Affiliated Children's Hospital of Fudan University on March 5, 2021 was selected as the study subject. Whole exome sequencing (WES) was carried out for the child, and candidate variant was verified by Sanger sequencing. The level of creatine in the brain was determined by magnetic resonance spectroscopy. RESULTS: The patient, a 1-year-and-10-month male, had presented with developmental delay and epilepsy. Both his mother and grandmother had a history of convulsions. MRS showed reduced cerebral creatine in bilateral basal ganglia and thalamus. The child was found to harbor a hemizygous splicing variant of the SLC6A8 gene, namely c.1767+1_1767+2insA, which may lead to protein truncation. The variant was not found in the public databases. Both his mother and grandmother were heterozygous carriers for the same variant. CONCLUSION The hemizygous c.1767+1_1767+2insA variant of the SLC6A8 gene probably underlay the CCDS in this child. Discovery of the novel variant has also expanded the mutational spectrum of the SLC6A8 gene.
Humans ; Male ; Amino Acid Metabolism, Inborn Errors ; Brain ; Creatine/genetics* ; Heterozygote ; Mothers ; Nerve Tissue Proteins ; Plasma Membrane Neurotransmitter Transport Proteins/genetics* ; Infant

Humans ; Amino Acid Metabolism, Inborn Errors/genetics* ; Haploinsufficiency

OBJECTIVE: To explore the clinical and genetic characteristics of four patients with medium-chain acyl-CoA dehydrogenase deficiency (MCADD). METHODS: Four children who had presented at the Children's Hospital Affiliated to Zhengzhou University between August 2019 and August 2021 were selected as the study subjects. Clinical data of the children were collected. The children were subjected to whole exome sequencing (WES). RESULTS: All of the four children were diagnosed with MCADD. Blood amino acid and ester acyl carnitine spectrum test showed that the concentration of octanoyl carnitine (C8) was significantly increased. The main clinical manifestations included poor mental response (3 cases), intermittent diarrhea with abdominal pain (1 case), vomiting (1 case), increased transaminase (3 cases), and metabolic acidosis (2 cases). Five variants were identified by genetic testing, among which c.341A>G (p.Y114C) was unreported previously. Three were missense variants, one was frameshift variant and one was splicing variant. CONCLUSION The clinical heterogeneity of MCADD is obvious, and the severity of the disease may vary. WES can assist with the diagnosis. Delineation of the clinical symptoms and genetic characteristics of the disease can facilitate early diagnosis and treatment of the disease.
Child ; Humans ; Acyl-CoA Dehydrogenase/genetics* ; Carnitine ; Genetic Testing ; Lipid Metabolism, Inborn Errors/genetics* ; Neonatal Screening

Renal calculus is a common disease with complex etiology and high recurrence rate. Recent studies have revealed that gene mutations may lead to metabolic defects which are associated with the formation of renal calculus, and single gene mutation is involved in relative high proportion of renal calculus. Gene mutations cause changes in enzyme function, metabolic pathway, ion transport, and receptor sensitivity, causing defects in oxalic acid metabolism, cystine metabolism, calcium ion metabolism, or purine metabolism, which may lead to the formation of renal calculus. The hereditary conditions associated with renal calculus include primary hyperoxaluria, cystinuria, Dent disease, familial hypomagnesemia with hypercalciuria and nephrocalcinosis, Bartter syndrome, primary distal renal tubular acidosis, infant hypercalcemia, hereditary hypophosphatemic rickets with hypercalciuria, adenine phosphoribosyltransferase deficiency, hypoxanthine-guanine phosphoribosyltransferase deficiency, and hereditary xanthinuria. This article reviews the research progress on renal calculus associated with inborn error of metabolism, to provide reference for early screening, diagnosis, treatment, prevention and recurrence of renal calculus.
Infant ; Humans ; Hypercalciuria/genetics* ; Kidney Calculi/genetics* ; Urolithiasis/genetics* ; Nephrocalcinosis/genetics* ; Metabolism, Inborn Errors/genetics*

OBJECTIVE: To carry out preimplantation genetic testing for monogenic/single gene disorders (PGT-M) for a Chinese family affected with Molybdenum co-factor deficiency due to pathogenic variant of MOCS2 gene. METHODS: A family with molybdenum co-factor deficiency who attended to the Maternal and Child Health Care Hospital of Guangxi Zhuang Autonomous Region in April 2020 was selected as the research subject. Trophoblast cells were biopsied from blastocysts fertilized by intracytoplasmic sperm injection. Embryos carrying the MOCS2 gene variant and chromosome copy number variation (CNV) of more than 4 Mb were detected by single-cell whole genome amplification, high-throughput sequencing and single nucleotide polymorphism typing. Embryos without or carrying the heterozygous variant and without abnormal chromosome CNV were transplanted. During mid-pregnancy, amniotic fluid sample was collected for prenatal diagnosis to verify the results of PGT-M. RESULTS: Eleven oocytes were obtained, among which three blastocysts were formed through culturing. Results of genetic testing suggested that one embryo was heterozygous for the maternally derived MOCS2 gene variant and without chromosomal CNV. Following embryo transfer, intrauterine singleton pregnancy was attained. Prenatal diagnosis by amniocentesis at 18 weeks of gestation revealed that the MOCS2 gene variant and chromosomal analysis results were both consistent with that of PGT-M, and a healthy male infant was born at 37⁺⁵ weeks of gestation. CONCLUSION PGT-M has helped the couple carrying the MOCS2 gene variant to have a healthy offspring, and may become an important method for couples carrying other pathogenic genetic variants.
Female ; Humans ; Pregnancy ; Aneuploidy ; China ; DNA Copy Number Variations ; Genetic Testing/methods* ; Preimplantation Diagnosis/methods* ; Metal Metabolism, Inborn Errors/genetics*