The cryo-EM structure of trypanosome 3-methylcrotonyl-CoA carboxylase provides mechanistic and dynamic insights into its enzymatic function.

3-Methylcrotonyl-CoA carboxylase (MCC) catalyzes the two-step, biotin-dependent production of 3-methylglutaconyl-CoA, an essential intermediate in leucine catabolism. Given the critical metabolic role of MCC, deficiencies in this enzyme lead to organic aciduria, while its overexpression is linked to tumor development. MCC is a dodecameric enzyme composed of six copies of each α- and ß-subunit. We present the cryo-EM structure of the endogenous MCC holoenzyme from Trypanosoma brucei in a non-filamentous state at 2.4 Å resolution. Biotin is covalently bound to the biotin carboxyl carrier protein domain of α-subunits and positioned in a non-canonical pocket near the active site of neighboring ß-subunit dimers. Moreover, flexibility of key residues at α-subunit interfaces and loops enables pivoting of α-subunit trimers to partly reduce the distance between α- and ß-subunit active sites, required for MCC catalysis. Our results provide a structural framework to understand the enzymatic mechanism of eukaryotic MCCs and to assist drug discovery against trypanosome infections.

GGCX mutants that impair hemostasis reveal the importance of processivity and full carboxylation to VKD protein function.

γ-Glutamyl carboxylase (GGCX) generates multiple carboxylated Glus (Glas) in vitamin K-dependent (VKD) proteins that are required for their functions. GGCX is processive, remaining bound to VKD proteins throughout multiple Glu carboxylations, and this study reveals the essentiality of processivity to VKD protein function. GGCX mutants (V255M and S300F) whose combined heterozygosity in a patient causes defective clotting and calcification were studied using a novel assay that mimics in vivo carboxylation. Complexes between variant carboxylases and VKD proteins important to hemostasis (factor IX [FIX]) or calcification (matrix Gla protein [MGP]) were reacted in the presence of a challenge VKD protein that could potentially interfere with carboxylation of the VKD protein in the complex. The VKD protein in the complex with wild-type carboxylase was carboxylated before challenge protein carboxylation occurred and became fully carboxylated. In contrast, the V255M mutant carboxylated both forms at the same time and did not completely carboxylate FIX in the complex. S300F carboxylation was poor with both FIX and MGP. Additional studies analyzed FIX- and MGP-derived peptides containing the Gla domain linked to sequences that mediate carboxylase binding. The total amount of carboxylated peptide generated by the V255M mutant was higher than that of wild-type GGCX; however, the individual peptides were partially carboxylated. Analysis of the V255M mutant in FIX HEK293 cells lacking endogenous GGCX revealed poor FIX clotting activity. This study shows that disrupted processivity causes disease and explains the defect in the patient. Kinetic analyses also suggest that disrupted processivity may occur in wild-type carboxylase under some conditions (eg, warfarin therapy or vitamin K deficiency).

GGCX-related congenital combined vitamin K-dependent clotting factors deficiency-1: Description of a fetus with chondrodysplasia punctata.

Congenital combined vitamin K-dependent clotting factors deficiency (VKCFD) is a rare autosomal recessive disease resulting in hemorrhagic symptoms usually associated with developmental disorders and bone abnormalities. Pathogenic variants in two genes encoding enzymes of the vitamin K cycle, GGCX and VKORC1, can lead to this disorder. We present the case of a male fetus with a brachytelephalangic chondrodysplasia punctata (CDP), absence of nasal bone, growth restriction, and bilateral ventriculomegaly at 18 weeks of gestation. Pathological examination showed a Binder phenotype, hypoplastic distal phalanges, stippled epiphyses, and brain abnormalities suggestive of a brain hemorrhage. Two GGCX pathogenic variants inherited respectively from the mother and the father were identified. To our knowledge, this is the first prenatal description of VKCFD. Even if it remains a rare etiology, which is mostly described in children or adult patients, VKCFD should be considered in fetuses with CDP.

[Analysis of MCCC2 gene variant in a pedigree affected with 3-methylcrotonyl coenzyme A carboxylase deficiency].

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). CONCLUSION: 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.

SNPs in SNCA, MCCC1, DLG2, GBF1 and MBNL2 are associated with Parkinson's disease in southern Chinese population.

Numerous single nucleotide polymorphisms (SNPs), which have been identified as susceptibility factors for Parkinson's disease (PD) as per genome-wide association studies, have not been fully characterized for PD patients in China. This study aimed to replicate the relationship between 12 novel SNPs of 12 genes and PD risk in southern Chinese population. Twelve SNPs of 12 genes were detected in 231 PD patients and 249 controls, using the SNaPshot technique. Meta-analysis was used to assess heterogeneity of effect sizes between this study and published data. The impact of SNPs on gene expression was investigated by analysing the SNP-gene association in the expression quantitative trait loci (eQTL) data sets. rs8180209 of SNCA (allele model: P = .047, OR = 0.77; additive model: P = .047, OR = 0.77), rs2270968 of MCCC1 (dominant model: P = .024, OR = 1.52), rs7479949 of DLG2 (recessive model; P = .019, OR = 1.52), rs10748818 of GBF1 (additive model: P < .001, OR = 0.37), and rs4771268 of MBNL2 (recessive model: P = .003, OR = 0.48) were replicated to be significantly associated with the increased risk of PD. Noteworthy, a meta-analysis of previous studies suggested rs8180209, rs2270968, rs7479949 and rs4771268 were in line with those of our cohort. Our study replicated five novel functional SNPs in SNCA, MCCC1, DLG2, GBF1 and MBNL2 could be associated with increased risk of PD in southern Chinese population.

MCCC2 overexpression predicts poorer prognosis and promotes cell proliferation in colorectal cancer.

PURPOSES: Recently, Methylcrotonoyl-CoA carboxylase 2 (MCCC2) is reported to be involved in tumor formation and progression. However, MCCC2 has nerve been reported in colorectal cancer. In this study, we aimed to investigate the role of MCCC2 in colorectal cancer. METHODS: 118 colorectal cancer and matched adjacent normal tissues were enrolled in this study. The expression level of MCCC2 was measured by quantificational real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC). The clinical significance of MCCC2 and its influence on cell proliferation was further analyzed. RESULTS: Results shown that the mRNA levels of MCCC2 in colorectal cancer tissues were significantly increased compared with those in normal tissues (P < .0001). MCCC2 high-expression was observed in 56.8% colorectal cancer tissues, which was significantly higher than those in normal controls (9.3%, P < .0001). MCCC2 high-expression correlated with tumor size, T stage, lymph node metastasis, distant metastasis, clinical stage and differentiation in colorectal cancer (P < .05). Moreover, MCCC2 high-expression predicted poorer prognosis and could be as an independent prognostic factor. In addition, MCCC2 knockdown significantly inhibited cell proliferation compared with these controls, while MCCC2 overexpression could reverse the effect. CONCLUSION: These data indicate MCCC2 overexpression promotes cell proliferation and predicts poorer prognosis in colorectal cancer.

Effect of GGCX on the differentiation function of osteoporosis bone marrow mesenchymal stem cells through regulating TGFß/smad signaling pathway.

OBJECTIVE: Osteoporosis (OP) has a high incidence and can be found in multiple age groups. The bone marrow mesenchymal stem cells (BMSCs) have the potential for self-renewal and multi-directional differentiation, which are often used for investigating the differentiation function of osteoporosis bone marrow mesenchymal stem cells. γ-glutamyl carboxylase (GGCX) is a carboxylase-related carboxylase and was observed to be abnormally expressed in osteoarthritis. However, the role and related mechanisms of GGCX in OP have not been fully elucidated. This work aimed to evaluate the effect of GGCX on the differentiation function of BMSCs. PATIENTS AND METHODS: Sprague-Dawley rats were randomly divided into the OP group prepared by ovariectomy and sham group. GGCX expression was tested by enzyme-linked immunosorbent assay (ELISA). BMSCs were isolated from OP rats and transfected with pcDNA-GGCX plasmids. BMSC proliferation was detected by tetrazolium salt colorimetry (MTT) assay. The osteogenic and adipogenic differentiation of BMSCs was analyzed by alizarin red staining and oil red O staining. The ALP activity was determined by alkaline phosphatase (ALP) activity colorimetric assay. Real time-PCR was used to test the expressions of osteogenesis-related genes RUNX2 and OPN mRNA. Western blot was adopted to assess the TGFß/smad signaling pathway activity. RESULTS: GGCX expression was significantly decreased in the serum of OP rats compared with the sham group (p < 0.05). The transfection of pcDNA-GGCX plasmid significantly promoted BMSC cell proliferation, increased calcified nodule formation, inhibited adipogenic differentiation, enhanced ALP activity, elevated RUNX2, and OPN mRNA expressions, and upregulated TGFß1, Smad2, and Smad7 expressions (p < 0.05). CONCLUSIONS: GGCX secretion is reduced in osteoporosis. GGCX can regulate osteoporosis via promoting the TGFß/smad signaling pathway, facilitating BMSCs osteogenic differentiation, and inhibiting BMSCs adipogenic differentiation.

Impact of genetic and clinical factors on warfarin therapy in patients early after heart valve replacement surgery.

PURPOSE: Factors influencing responsiveness to warfarin at treatment onset time were not well identified in Chinese patients undergoing heart valve replacement. We sought to select the most relevant factors that associated with patient response to warfarin early after heart valve surgery. METHODS: In this observational study, 289 patients starting warfarin therapy early after heart valve replacement surgery were enrolled. CYP2C9 *1, *2, *3, and *5; VKORC1-1639 G>A, CYP4F2 V433M, and GGCX rs11676382 genotypes; clinical characteristics, response to therapy, and bleeding and thrombosis events were collected. The primary outcomes were the time to the first INR equal to or more than lower limit of therapeutic range and the warfarin dose requirements. Stepwise multiple linear regression was performed to develop a dosing algorithm to predict the warfarin dose requirements. RESULTS: The results of univariate analysis showed lone VKORC1-1639 G>A, CYP2C9 *1/*3, cefazolin, cefoperazone-sulbactam, increased BMI, Δhemoglobin, and white blood cell count could significantly affect patient responsiveness to warfarin in the initial period of anticoagulation. Multivariate analysis resulted in an equation: Accumulated warfarin doses (mg) = 17.068 VKORC1-1639 G>A - 4.261 hypertension + 0.593 BMI - 0.115 age - 4.852 CYP2C9 *1/*3 - 2.617 cefazolin - 4.902 cefoperazone-sulbactam - 4.537, which could explain 40.2% of the variability in warfarin dose needed to reach the first INR equal to or more than lower limit of therapeutic range. CONCLUSIONS: Both genetic and clinical factors contributed to anticoagulation effect of warfarin in the initial period of treatment. Our findings could provide a basis for the personalized management of warfarin use in the early stage of anticoagulation in northern Chinese patients.

A novel multidomain acyl-CoA carboxylase in Saccharopolyspora erythraea provides malonyl-CoA for de novo fatty acid biosynthesis.

Acetyl-CoA carboxylases (ACCs) are enzyme complexes generally composed of three catalytic domains and distributed in all organisms. In prokaryotes and plastids of most plants, these domains are encoded in distinct subunits forming heteromeric complexes. Distinctively, cytosolic ACCs from eukaryotes and plastids of graminaceous monocots, are organized in a single multidomain polypeptide. Until now, no multidomain ACCs had been discovered in bacteria. Here, we show that a putative multidomain ACC in Saccharopolyspora erythraea is encoded by the sace_4237 gene, representing the first prokaryotic ACC homodimeric multidomain complex described. The SACE_4237 complex has both acetyl-CoA and propionyl-CoA carboxylase activities. Importantly, we demonstrate that sace_4237 is essential for S. erythraea survival as determined by the construction of a sace_4237 conditional mutant. Altogether, our results show that this prokaryotic homodimeric multidomain ACC provides malonyl-CoA for de novo fatty acid biosynthesis. Furthermore, the data presented here suggests that evolution of these enzyme complexes, from single domain subunits to eukaryotic multidomain ACCs, occurred in bacteria through domain fusion.

Methylcrotonoyl-CoA carboxylase 2 overexpression predicts an unfavorable prognosis and promotes cell proliferation in breast cancer.

Aim: Methylcrotonoyl-CoA carboxylase 2 (MCCC2), a  subunit of 3-Methylcrotonyl-CoA carboxylase (MCC), is reported to be involved in tumor formation and development. However, the role of MCCC2 in breast cancer is unknown. Materials & methods: MCCC2 expression was examined in 138 cases of breast cancer and matched adjacent normal tissues by quantitative reverse transcription PCR and immunohistochemistry. The influence of MCCC2 expression on cell proliferation was evaluated by CCK-8 and colony formation assay. Results: Quantitative reverse transcription PCR results show MCCC2 mRNA levels were significantly greater in breast cancer tissues than normal tissues (p < 0.05). Immunohistochemistry analysis revealed that MCCC2 overexpression was significantly associated with Tumor, Node, Metastasis stage and lymph node metastasis and predicted an unfavorable prognosis (p < 0.05). CCK-8 and colony formation assay indicated that MCCC2 overexpression significantly promoted cell proliferation. Discussion & conclusion: These data indicate MCCC2 overexpression predicts an unfavorable prognosis and promotes cell proliferation in breast cancer, which may serve as a potential prognostic biomarker.

Congenital Combined Deficiency of the Vitamin K-dependent Clotting Factors (VKCFD): A Novel Gamma-glutamyl Carboxylase (GGCX) Mutation.

Congenital combined vitamin K-dependent clotting factors deficiency (VKCFD) is a very rare autosomal recessive bleeding disorder. Here we report a case of a girl with novel variant in the gamma-glutamyl carboxylase (GGCX) gene leading to VKCFD. A 3-month-old girl presented to our hospital with a history of bleeding from puncture site. Laboratory evaluation showed markedly prolonged partial thromboplastin time and activated partial thromboplastin time. Activities of vitamin K-dependent factors were all low. Genetic analysis revealed a homozygous currently unreported variant in the GGCX gene further supporting a diagnosis of VKCFD type 1. VKCFD due to GGCX mutation has an overall good prognosis.

Zinc alpha2 glycoprotein promotes browning in adipocytes.

Recent studies have highlighted recruiting and activating brite adipocytes in WAT (so-called "browning") would be an attractive anti-obesity strategy. Zinc alpha2 glycoprotein (ZAG) as an important adipokine, is reported to ameliorate glycolipid metabolism and lose body weight in obese mice. However whether the body reducing effect mediated by browning programme remains unclear. Here, we show that overexpression of ZAG in 3T3-L1 adipocytes enhanced expression of brown fat-specific markers (UCP-1, PRDM16 and CIDEA), mitochondrial biogenesis genes (PGC-1α, NRF-1/2 and mtTFA) and the key lipid metabolism lipases (ATGL, HSL, CPT1-A and p-acyl-CoA carboxylase). Additionally, those effects were dramaticlly abolished by H89/SB203580, revealing ZAG-induced browning depend on PKA and p38 MAPK signaling. Overall, our findings suggest that ZAG is a candidate therapeutic agent against obesity via induction of brown fat-like phenotype in white adipocytes.

Effects of GGCX overexpression on anterior cruciate ligament transection-induced osteoarthritis in rabbits.

Effective therapeutic methods for osteoarthritis (OA) are lacking. γ­glutamyl carboxylase (GGCX) is a key enzyme that regulates carboxylation of cartilage matrix Gla protein (MGP). Whether GGCX overexpression protects against OA remains unknown. The aim of the present study was to explore the effects of GGCX overexpression on anterior cruciate ligament transection (ACLT)­induced OA and its mechanisms in Japanese white rabbits. ACLT surgery was used to establish an OA model in rabbits. A total of 48 rabbits were randomly divided into 4 groups: Sham, OA model + GGCX overexpression plasmid, OA model + saline and OA model + empty vector. The expression of uncarboxylated MGP (ucMGP), carboxylated MGP (cMGP), matrix metalloproteinase (MMP)­13, collagen type X, collagen type II, tumor necrosis factor (TNF)­α and interleukin (IL)­1ß were detected by ELISA, immunohistochemistry, reverse transcription­quantitative polymerase chain reaction and western blotting. Morphological changes to tibial cartilage were assessed by Giemsa and safranin O­fast green staining, respectively. Compared with the Sham control, GGCX expression was significantly decreased in the OA Model group. GGCX expression was increased by injection of a lentivirus­carried overexpression plasmid that encoded GGCX. GGCX overexpression ameliorated ATLC­induced damage in articular cartilage. OA Model rabbits exhibited significantly decreased expression levels of cMGP and collagen type II, and increased expression of ucMGP, collagen type X, MMP­13, IL­1ß and TNF­α. Notably, these expression levels were reversed by GGCX overexpression in OA Model rabbits. Results from the present study indicated that GGCX expression was decreased in OA Model rabbits, whereas overexpression of GGCX was able to promote carboxylation of MGP, reduce inflammation, decrease MMP­13 expression and regulate collagen expression. The results also indicated that GGCX may serve as a therapeutic target for OA.

Calcification in dermal fibroblasts from a patient with GGCX syndrome accompanied by upregulation of osteogenic molecules.

Gamma-glutamyl carboxylase (GGCX) gene mutation causes GGCX syndrome (OMIM: 137167), which is characterized by pseudoxanthoma elasticum (PXE)-like symptoms and coagulation impairment. Here, we present a 55-year-old male with a novel homozygous deletion mutation, c.2,221delT, p.S741LfsX100, in the GGCX gene. Histopathological examination revealed calcium deposits in elastic fibers and vessel walls, and collagen accumulation in the mid-dermis. Studies of dermal fibroblasts from the patient (GGCX dermal fibroblasts) demonstrated that the mutated GGCX protein was larger, but its expression level and intracellular distribution were indistinguishable from those of the wild-type GGCX protein. Immunostaining and an enzyme-linked immunosorbent assay showed an increase in undercarboxylated matrix gamma-carboxyglutamic acid protein (ucMGP), a representative substrate of GGCX and a potent calcification inhibitor, indicating that mutated GGCX was enzymatically inactive. Under osteogenic conditions, calcium deposition was exclusively observed in GGCX dermal fibroblasts. Furthermore, GGCX dermal fibroblast cultures contained 23- and 7.7-fold more alkaline phosphatase (ALP)-positive cells than normal dermal fibroblast cultures (n = 3), without and with osteogenic induction, respectively. Expression and activity of ALP were higher in GGCX dermal fibroblasts than in normal dermal fibroblasts upon osteogenic induction. mRNA levels of other osteogenic markers were also higher in GGCX dermal fibroblasts than in normal dermal fibroblasts, which including bone morphogenetic protein 6, runt-related transcription factor 2, and periostin (POSTN) without osteogenic induction; and osterix, collagen type I alpha 2, and POSTN with osteogenic induction. Together, these data indicate that GGCX dermal fibroblasts trans-differentiate into the osteogenic lineage. This study proposes another mechanism underlying aberrant calcification in patients with GGCX syndrome.

[ANALYSIS OF γ-GLUTAMYL CARBOXYLASE GENE rs2592551 POLYMORPHISM ASSOCIATION WITH ISCHEMIC ATHEROTHROMBOTIC STROKE].

The results of γ-glutamyl carboxylase gene rs2592551 polymorphism determining in 170 patients with ischemic atherothrombotic stroke and 124 subjects without acute cerebrovascular disease (control group) have been evaluated. Obtained results revealed that rs2592551 polymorphism was related to ischemic stroke in Ukrainian population. The risk for this disease in patients with T/T genotype was higher than in major C-allele carriers (odds ratio (OR) = 3.117; 95% confidence interval (CI) = 1.016-9.566; P = 0.047). After dividing patients into subgroups, formed by the presence of certain risk factors for atherosclerosis, similar association has been established for women and non-smokers. At the same time, the heterozygous genotype (C/T) in females had significantly protective effect against ischemic stroke development when compared to C/C and T/T genotypes (OR = 0.460; 95% CI 0.213-0.994; P = 0.048). Statistical significance of these results persisted even after adjustment for age, body mass index, smoking and hypertension.

[A novel compound heterozygous mutation causing 3-methylcrotonyl-CoA carboxylase deficiency].

OBJECTIVE: To explore the molecular mechanism for a boy suspected with 3-methylcrotonyl-CoA carboxylase deficiency by neonatal screening. METHODS: PCR and Sanger sequencing were used to identify potential mutations of MCCC1 and MCCC2 genes. SIFT and Polyphen-2 software was used to predict the effect of variant on the protein function and conservation of the variant across various species. Human Splicing Finder and Swiss-PdbViewer4.1.0 were applied to analyze the possible mechanism of the variant. RESULTS: For the proband, a compound heterozygous mutation was discovered in the MCCC1 gene, namely c.539G>T (p.G180V) and c.704_711del (p.A235Vfs*4), which were inherited from his father and mother, respectively. The two mutations have disrupted the protein conformation, which in turn may impact the function of MCC protein. CONCLUSION: The compound heterozygous mutations of the MCCC1 gene may contribute to the 3-methylcrotonyl-CoA carboxylase deficiency manifested by the patient.

Frameshift mutations of OGDH, PPAT and PCCA genes in gastric and colorectal cancers.

Metabolic reprogramming is a hallmark of cancer. However, genetic alterations in metabolism-related genes are largely unknown. The aim of this study was to identify whether somatic mutations in OGDH, PPAT and PCCA genes known to be involved in amino acid or nucleotide metabolism are mutated in gastric cancer (GC) and colorectal cancer (CRC). By public database search, we identified that OGDH, PPAT and PCCA genes harbor mononucleotide repeats that may serve as mutation targets in cancers with microsatellite instability (MSI). We analyzed the repeats for the presence of the mutations in 90 GCs and 141 CRCs using single-strand conformation polymorphism (SSCP) and samples of 10 patients with shifted bands were sequenced. We found frameshift mutations of OGDH (3 cases), PCCA (5 cases) and PPAT (2 cases) in the cancers. These mutations were exclusively detected in MSI-high (MSI-H), and not in MSI-low or MSI-stable (MSI-L/MSS) cancers. We also analyzed 16 CRCs for the presence of intratumoral heterogeneity (ITH) and found that one CRC harbored regional ITH for OGDH frameshift mutation showing very rare frequency of OGDH mutation ITH in colorectal cancer tissues. Our data indicate that amino acid/nucleotide metabolism-related genes OGDH, PPAT and PCCA acquire somatic mutations in MSH-H GCs and CRCs and that mutational ITH may occur in at least some of these tumors. Collectively, our results may extend our insight into the involvement of amino acid/nucleotide metabolism in the pathogenesis of cancer for, in particular, MSI-H GCs and CRCs.

[Pseudoxanthoma elasticum-like disease with deficiency of vitamin K-dependent clotting factors and cutis laxa features]. / Pseudoxanthome élastique variant avec déficit en facteurs de coagulation vitamine K-dépendants et perte d'élasticité cutanée.

BACKGROUND: Pseudoxanthoma elasticum (PXE)-like syndrome is characterized by the association of PXE and cutis laxa (CL) features with a deficiency of vitamin K-dependent clotting factors. It was first described in 1971 and was identified as a distinct genetic entity in 2007 with analysis of the GGCX (γ-glutamyl carboxylase) gene, which is involved in congenital deficiency in vitamin K-dependent clotting factors. Here we report a new case of this extremely rare syndrome. PATIENTS AND METHODS: A 23-year-old female patient was seen for the emergence of loose and redundant skin following extensive weight loss. She also presented a deficiency of vitamin K-dependent clotting factors. Physical examination revealed excessive, leathery skin folds in the axillary and neck regions. A skin biopsy revealed polymorphous and fragmented elastic fibers in the reticular dermis. These were mineralized, as was demonstrated by Von Kossa staining. The clinical features of CL associated with the histopathological features of PXE and vitamin K-dependent clotting factor deficiency led us to a diagnosis of PXE-like syndrome. A molecular study of the GGCX gene showed compound heterozygosity. DISCUSSION: The GGCX gene is usually responsible for PXE-like syndrome. GGCX encodes a γ-glutamyl carboxylase necessary for activation of gla-proteins. Gla-proteins are involved both in coagulation factors in the liver and in the prevention of ectopic mineralization of soft tissues. Uncarboxylated forms of gla-proteins in fibroblast would thus enable mineralization and fragmentation of elastic fibers.