OBJECTIVE: To investigate the clinical and genetic features of children with 3-methylcrotonyl-coenzyme A carboxylase deficiency (MCCD).
METHODS: A retrospective analysis was conducted on the clinical manifestations and genetic testing results of six children with MCCD who attended Children\'s Hospital Affiliated to Zhengzhou University from January 2018 to October 2023.
RESULTS: Among the six children with MCCD, there were 4 boys and 2 girls, with a mean age of 7 days at the time of attending the hospital and 45 days at the time of confirmed diagnosis. Of all children, one had abnormal urine odor and five had no clinical symptoms. All six children had increases in blood 3-hydroxyisovaleryl carnitine and urinary 3-hydroxyisovaleric acid and 3-methylcrotonoylglycine, and five of them had a reduction in free carnitine. A total of six mutations were identified in the MCCC1 gene, i.e., c.1630del(p.R544Dfs*2), c.269A>G(p.D90G), c.1609T>A(p.F537I), c.639+2T>A, c.761+1G>T, and c.1331G>A(p.R444H), and three mutations were identified in the MCCC2 gene, i.e., c.838G>T(p.D280Y), c.592C>T(p.Q198*,366), and c.1342G>A(p.G448A). Among these mutations, c.269A>G(p.D90G) and c.1609T>A(p.F537I) had not been previously reported in the literature. There was one case of maternal MCCD, and the child carried a heterozygous mutation from her mother. Five children with a reduction in free carnitine were given supplementation of L-carnitine, and free carnitine was restored to the normal level at the last follow-up visit.
CONCLUSIONS: This study identifies two new mutations, c.269A>G(p.D90G) and c.1609T>A(p.F537I), thereby expanding the mutation spectrum of the MCCC1 gene. A combination of blood amino acid and acylcarnitine profiles, urine organic acid analysis, and genetic testing can facilitate early diagnosis and treatment of MCCD, and provide essential data for genetic counseling.
目的: 探讨3-甲基巴豆酰辅酶A羧化酶缺乏症（3-methylcrotonyl-coenzyme A carboxylase deficiency, MCCD）患儿的临床及遗传学特征。方法: 回顾性分析2018年1月—2023年10月就诊于郑州大学附属儿童医院的6例MCCD患儿的临床表现及基因检测结果。结果: 6例MCCD患儿中，男性4例，女性2例，平均就诊年龄为7 d，平均确诊年龄为45 d。1例小便气味异常，5例无临床症状。6例患儿血3-羟基异戊酰肉碱、尿3-羟基异戊酸、3-甲基巴豆酰甘氨酸均增高，5例伴游离肉碱降低。共检出MCCC1基因变异6个：c.1630del(p.R544Dfs*2)、c.269A>G(p.D90G)、c.1609T>A(p.F537I)、c.639+2T>A、c.761+1G>T、c.1331G>A(p.R444H)，以及MCCC2基因变异3个：c.838G>T(p.D280Y)、c.592C>T(p.Q198*, 366)、c.1342G>A(p.G448A)，其中MCCC1基因c.269A>G(p.D90G)、c.1609T>A(p.F537I)未见文献报道。1例为母源性MCCD，患儿携带来自母亲的一个杂合变异。5例伴游离肉碱降低患儿予补充左卡尼汀，末次随访时游离肉碱均恢复至正常水平。结论: MCCC1基因c.269A>G(p.D90G)、c.1609T>A(p.F537I)为新发现的变异，丰富了MCCC1基因变异谱。血氨基酸及酰基肉碱谱和尿有机酸谱联合基因检测有助于MCCD早期诊断和治疗，并为遗传咨询提供参考。.

OBJECTIVE: To observe the effect of Shenqi Chongcao (SQCC) Formula on the ASS1/src/STAT3 signaling pathway in a rat model of lung fibrosis and explore its therapeutic mechanism.
METHODS: A total of 120 male SD rats were divided equally into 5 groups, including a blank control group with saline treatment and 4 groups of rat models of idiopathic pulmonary fibrosis induced by intratracheal instillation of bleomycin. One day after modeling, the rat models were treated with daily gavage of 10 mL/kg saline, SQCC decoction (0.423 g/kg), pirfenidone (10 mL/kg), or intraperitoneal injection of arginine deiminase (ADI; 2.25 mg/kg, every 3 days) for 28 days. After the treatments, the lung tissues of the rats were collected for calculating the lung/body weight ratio, observing histopathology using HE and Masson staining, and analyzing the inflammatory cells in BALF using Giemsa staining. Serum chemokine ligand 2 (CCL2) and transforming growth factor-β1 (TGF-β1) levels were measured with ELISA. The protein expressions of src, p-srcTry529, STAT3, and p-STAT3Try705 and the mRNA expressions of ASS1, src and STAT3 in the lung tissues were detected using Western blotting and RT-qPCR.
RESULTS: The neutrophil, macrophage and lymphocyte counts and serum levels of CCL2 and TGF-β1 were significantly lower in SQCC, pirfenidone and ADI treatment groups than in the model group at each time point of measurement (P < 0.05). P-srcTry529 and p-STAT3Try705 protein expression levels and ASS1, src, and STAT3 mRNA in the lung tissues were also significantly lower in the 3 treatment groups than in the model group (P < 0.05).
CONCLUSIONS: SQCC Formula can alleviate lung fibrosis in rats possibly by activating the ASS1/src/STAT3 signaling pathway in the lung tissues.

OBJECTIVE: This study aimed to investigate the effect and mechanism of methylcrotonyl-CoA carboxylase subunit 1 (MCCA) on multidrug resistance in multiple myeloma (MM).
METHODS: The apoptosis kit and CCK-8 reagent were used to detect drug-induced cell apoptosis and viability. Immunoprecipitation, immunofluorescence staining, and protein structural simulation were used to detect the interaction between MCCA and Bad. Immunodeficient mice were injected with ARD cells and treated with bortezomib. Changes in tumor burden were recorded by bioluminescence imaging, and κ light chain content in the blood of mice was detected by enzyme-linked immunoassay.
RESULTS: Patients with high MCCA expression from a primary MM dataset had superior overall survival. After treatment with different anti-MM drugs, MCCA knockdown MM (MCCA-KD) cells had higher survival rates than control knockdown (CTR-KD) cells (p < 0.05). Mechanistic studies have revealed that MCCA-KD cells had dysfunctional mitochondria with decreased Bax and Bad levels and increased Bcl-xl and Mcl-1 levels. Furthermore, that MCCA and Bad demonstrated protein-protein interactions. The half-life of Bad in MCCA-KD cells is significantly shorter than that in CTR-KD cells (7.34 vs. 2.42 h, p < 0.05). In a human MM xenograft mouse model, we confirmed that MCCA-KD tumors had a poor response to anti-MM drugs in vivo. Finally, we showed that MCCA might contribute to multidrug resistance in different human cancers, particularly in solid tumors.
CONCLUSIONS: Our findings demonstrated a novel function of MCCA in multidrug resistance. The lack of MCCA expression promoted antiapoptotic cell signaling in MM cells.

Identifying genes whose expression is associated with schizophrenia (SCZ) risk by transcriptome-wide association studies (TWAS) facilitates downstream experimental studies. Here, we integrated multiple published datasets of TWAS, gene coexpression, and differential gene expression analysis to prioritize SCZ candidate genes for functional study. Convergent evidence prioritized Propionyl-CoA Carboxylase Subunit Beta (PCCB), a nuclear-encoded mitochondrial gene, as an SCZ risk gene. However, the PCCB\'s contribution to SCZ risk has not been investigated before. Using dual luciferase reporter assay, we identified that SCZ-associated SNPs rs6791142 and rs35874192, two eQTL SNPs for PCCB, showed differential allelic effects on transcriptional activities. PCCB knockdown in human forebrain organoids (hFOs) followed by RNA sequencing analysis revealed dysregulation of genes enriched with multiple neuronal functions including gamma-aminobutyric acid (GABA)-ergic synapse. The metabolomic and mitochondrial function analyses confirmed the decreased GABA levels resulted from inhibited tricarboxylic acid cycle in PCCB knockdown hFOs. Multielectrode array recording analysis showed that PCCB knockdown in hFOs resulted into SCZ-related phenotypes including hyper-neuroactivities and decreased synchronization of neural network. In summary, this study utilized hFOs-based multi-omics analyses and revealed that PCCB downregulation may contribute to SCZ risk through regulating GABAergic pathways, highlighting the mitochondrial function in SCZ.

γ-glutamyl carboxylase (GGCX), also known as vitamin K-dependent glutamyl carboxylase, catalyzes the posttranslational modification of specific glutamate residues in vitamin K-dependent proteins (VKDPs), and participates multiple biological functions including blood coagulation, bone metabolism, vascular calcification, and cell proliferation. It has been reported originally that GGCX pathogenic variation causes blood coagulation deficiency, which is called as vitamin K-dependent coagulation factor deficiency 1 (VKCFD1). Recently, it has been found that GGCX gene variation results in multiple clinical phenotypes, including dermatological, ophthalmological, skeletal or cardiac abnormalities. Among them, dermatological phenotype is the most common, which is known as pseudoxanthoma elasticum-like syndrome. This paper has reviewed the GGCX pathogenic variation associated phenotypes, in order to increase the recognition of GGCX-related genetic diseases and to help its diagnosis and treatment.

OBJECTIVE: Propionic acidemia (PA) is an autosomal recessive metabolic disorder caused by a deficiency of propionyl-CoA carboxylase and mutations in the PCCA and PCCB genes. In this study, we investigated the clinical characteristics of individuals with PA and conducted genetic analyses to provide new genetic evidence for the diagnosis of PA.
METHODS: We conducted whole-exome sequencing and Sanger sequencing in four individuals with PA from three unrelated Chinese families. We also performed a structural analysis of the PCCB protein variants. Couples from the three families included in our study underwent in vitro fertilization with preimplantation genetic testing.
RESULTS: We found five variants of PCCB. These biallelic variants were inherited from heterozygous parental carriers and were located in the functional domain, absent in human population genome datasets, and predicted to be deleterious. These findings indicate that the variants might be responsible for the clinical features observed in these particular patients with PA. Through successful embryo transfer and implantation, one of the couples fortunately gave birth to a healthy child.
CONCLUSIONS: Overall, our study can expand the mutation spectrum of PCCB and provide useful information for the prenatal diagnosis of PA and genetic counseling for affected individuals.

UNASSIGNED: Propionic acidemia is associated with pathogenic variants in PCCA or PCCB gene. We investigated the potential pathogenic variants in PCCA or PCCB genes in Fujian Han population.Two probands and their families of Han ethnicity containing two generations were subject to newborn screening using tandem mass spectrometry, followed by diagnosis using urine gas chromatography mass spectrometry. Sanger sequencing was used to identify potential mutations in PCCA and PCCB genes.Compound heterozygous variants were identified in PCCB gene in two siblings of the first family, the youngest girl showed a novel missense variant c.1381G>C (p.Ala461Pro) in exon 13 and a heterozygous missense variant c.1301C>T (p.Ala434Val) in exon 13, which were inherited respectively from their parents. The oldest boy is a carrier with a novel missense variant c.1381G>C (p.Ala461Pro) in exon 13 which were inherited from his father. In the second family, c.1535G>A homozygous mutations were identified in the baby girl, which were inherited respectively from their parents. In silico analysis, several different types of bioinformatic software were utilized, which predicted that the novel variant c.1381G>C in PCCB gene was damaged. According to ACMG principle, the missense variant c.1381G>C (p.Ala461Pro) in exon 13 was a Variant of Undetermined Significance (VUS).One novel missense variant and two missense variants in PCCB gene were identified in the study. The novel variant of PCCB gene identified VUS was identified for the first time in the Chinese population, which enriched the mutational spectrum of PCCB gene.

OBJECTIVE: To explore the genetic basis for a child with clinically suspected 3-methylcrotonyl-coenzyme A carboxylase deficiency (MCCD).
METHODS: Genomic DNA was extracted from peripheral blood samples of the proband and her parents. Whole exome sequencing was used to screen pathogenic variant in the proband. Suspected variant was verified by Sanger sequencing. Impact of the variant on the structure and function of protein product was analyzed by using bioinformatic software.
RESULTS: Sanger sequencing showed that the proband has carried homozygous missense c.1342G>A (p.Gly448Ala) variant of the MCCC2 gene, for which her mother was a heterozygous carrier. The same variant was not detected in her father. The variant was predicted to be pathogenic by PolyPhen-2 and Mutation Taster software, and the site was highly conserved among various species. Based on the American College of Medical Genetics and Genomics standards and guidelines, the c.1342G>A (p.Gly448Ala) variant of MCCC2 gene was predicted to be likely pathogenic(PM2+PP2-PP5).
CONCLUSIONS: The homozygous missense variant of the MCCC2 gene c.1342G>A (p.Gly448Ala) probably underlay the molecular pathogenesis of the proband. Genetic testing has confirmed the clinical diagnosis.

BACKGROUND: Propionic acidemia (PA) is a severe monogenic disorder characterized by a deficiency of the mitochondrial protein propionyl-CoA carboxylase (PCC) enzyme, which is caused by mutations in the PCCA or PCCB gene. Preconception carrier screening could provide couples with meaningful information for their reproductive options; however, it is not widely performed in China.
METHODS: This report describes a case of dizygotic twin siblings conceived by in vitro fertilization (IVF) and diagnosed with propionic acidemia (PA). Their parents had no history of PA. Tandem mass spectrometry and urine gas chromatography/mass spectrometry (GC/MS) of the twin siblings revealed markedly elevated propionyl carnitine (C3), C3/C2, and 3-hydroxypropionate in the plasma and urine. Whole-exome sequencing was performed for the twin siblings. A homozygous missense mutation, c.2002G > A (p.Gly668Arg) in PCCA, was identified in the twin siblings. Sanger sequencing confirmed the homozygous mutation in the twin siblings and identified their parents as heterozygous carriers of the c.2002G > A mutation in PCCA. Both neonates in this case died. This is an emotionally and financially devastating outcome that could have been avoided with genetic carrier screening before conception. If couples are screened before IVF and found to be silent carriers, then reproductive options (such as preimplantation genetic diagnosis or prenatal diagnosis) can be offered to achieve a healthy newborn.
CONCLUSIONS: This case is a reminder to infertile couples seeking IVF that it is beneficial to clarify whether they are silent carriers before undergoing IVF.

BACKGROUND: Spinal muscular atrophy (SMA) is an autosomal recessive hereditary disease associated with severe muscle atrophy and weakness in the limbs and trunk. The discovery of mutated genes is helpful in diagnosis and treatment for SMA.
METHODS: Eighty-three whole blood samples were collected from 28 core families of clinically suspected SMA, and multiplex ligation probe amplification (MLPA) was performed. Afterwards, the complete gene sequence of SMN1 gene was detected. Furthermore, 20 SMA patients were selected from the 28 probands, and 5 non SMA children as controls. The Life Technologies SOLiD™ technology with mate-pair chemistry was utilized to conduct the whole exome high-throughput sequencing.
RESULTS: Twenty-two probands were SMA patients, 3 probands carriers, and 3 probands normal individuals. Moreover, 2 parents from 2 SMA families were with 3 SMN1 exon7 copies. Six SMN1 single nucleotide variants (SNVs) were identified in the 83 samples, and c.[84C > T], c.[271C > T], c.[-39A > G] and g.[70240639G > C] were novel. Compared with control group, 9102 mutation were selected out in SMA patients. SPTA1 mutation c.[-41_-40insCTCT], FUT5 SNV c.[1001A > G], and MCCC2 SNV c.[-117A > G] were the 3 most frequent mutations in SMA group (95, 85 and 75%, respectively).
CONCLUSIONS: We identified some mutations in both SMN1 and other genes, and c.[271C > T], c.[-41_-40insCTCT], c.[1001A > G] and c.[-117A > G] might be associated with the onset of SMA.