Noninvasive prenatal screening in a pregnant woman with a history of stem cell transplant from a male donor: A case report and literature review.

BACKGROUND: As a screening method, inaccuracies in noninvasive prenatal screening (NIPS) exist, which are often attributable to biological factors. One such factor is the history of transplantation. However, there are still limited reports on such NIPS cases. METHODS: We report an NIPS case of a pregnant woman who had received a stem cell transplant from a male donor. To determine the karyotype in the woman's original cell, we performed chromosome microarray analysis (CMA) on her postnatal blood and oral mucosa. To comprehensively estimate the cell-free DNA (cfDNA) composition, we further performed standard NIPS procedures on the postnatal plasma. Moreover, we reviewed all published relevant NIPS case reports about pregnant women with transplantation history. RESULTS: NIPS showed a low-risk result for common trisomies with a fetal fraction of 65.80%. CMA on maternal white blood cells showed a nonmosaic male karyotype, while the oral mucosa showed a nonmosaic female karyotype. The proportion of donor's cfDNA in postnatal plasma was 94.73% based on the Y-chromosome reads ratio. The composition of cfDNA in maternal plasma was estimated as follows: prenatally, 13.60% maternal, 65.80% donor, and 20.60% fetal/placental, whereas postnatally, 5.27% maternal and 94.73% donor. CONCLUSIONS: This study expanded our understanding of the influence of stem cell transplantation on NIPS, allowing us to optimize NIPS management for these women.

Creatine Kinase-MM/Proto-oncogene Tyrosine-Protein Kinase Receptor as a Sensitive Indicator for Duchenne Muscular Dystrophy Carriers.

Duchenne muscular dystrophy (DMD), a lethal X-linked recessive genetic disease, is characterized by progressive muscle wasting which will lead to premature death by cardiorespiratory complications in their late twenties. And 2.5-19% DMD carriers that also suffer from skeletal muscle damage or dilated cardiomyopathy when diagnosed as soon as possible is meaningful for prenatal diagnosis and advance warning for self-health. The current DMD carrier screening mainly relies on detecting serum creatine kinase activity, covering only 50-70% DMD carriers which will cause many false negatives and require the discovery of highly effective biomarker and simple detection procedure for DMD carriers. In this article, we have compiled a comprehensive summary of all documented biomarkers associated with DMD and categorized them based on their expression patterns. We specifically pinpointed novel DMD biomarkers, previously unreported in DMD carriers, and conducted further investigations to explore their potential. Compared to creatine kinase activity alone in DMD carriers, creatine kinase-MM can improve the specificity from 73 to 81%. And our investigation revealed another promising protein: proto-oncogene tyrosine-protein kinase receptor (RET). When combined with creatine kinase-MM (creatine kinase-MM/RET ratio), it significantly enhances the specificity (from 81 to 83%) and sensitivity (from 71.4 to 93%) of detecting DMD carriers in serum. Moreover, we successfully devised an efficient method for extracting RET from dried blood spots. This breakthrough allowed us to detect both creatine kinase-MM and RET using dried blood spots without compromising the detection rate.

Knockdown of lncRNA LINC00662 suppresses malignant behaviour of osteosarcoma cells via competition with miR-30b-3p to regulate ELK1 expression.

PURPOSE: Osteosarcoma is a type of bone malignancy that mainly occurred in teenagers. This investigation is aimed to clarify the effect of long non-coding RNA (lncRNA) LINC00662 on the proliferation, migration, and invasion in osteosarcoma and explore the underlying action mechanisms. METHODS: The mRNA expression of LINC00662 was determined by real-time quantitative polymerase chain reaction. Cell proliferation, migration, and invasion were evaluated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing, and transwell assays, respectively. A dual-luciferase reporter assay was used to validate the target relationships Between microRNA (miR)-30b-3p and LINC00662/ ETS domain-containing protein 1 (ELK1). Western blotting was performed to determine the protein expression of ELK1. Xenograft model was established to evaluate the effects of LINC00662 silencing on tumor growth in vivo. RESULTS: LncRNA LINC00662 and ELK1 were significantly increased, while miR-30b-3p was reduced in osteosarcoma tissues. The results of functional experiments indicated that transfection of small hairpin (sh)-LINC00662 and miR-30b-3p mimics repressed the migration, invasion, and proliferation of osteosarcoma cells. LncRNA LINC00662 also appeared to sponge miR-30b-3p in order to affect the expression of ELK1. Simultaneously, there were weak negative correlations between the expression of miR-30b-3p and LINC00662/ELK1 in osteosarcoma tissues. Rescue experiments suggested that ELK1 overexpression and downregulation of miR-30b-3p reversed the suppressive effects of sh-LINC00662 on the cell migration, invasion, and proliferation in osteosarcoma. CONCLUSIONS: The current study indicated that knockdown of LINC00662 repressed cell migration, invasion, and proliferation through sponging miR-30b-3p to regulate the expression of ELK1 in osteosarcoma. These results may uncover a promising target for the treatment of osteosarcoma.

A novel LGI1 mutation causing autosomal dominant lateral temporal lobe epilepsy confirmed by a precise knock-in mouse model.

AIMS: This study aimed to explore the pathomechanism of a mutation on the leucine-rich glioma inactivated 1 gene (LGI1) identified in a family having autosomal dominant lateral temporal lobe epilepsy (ADLTE), using a precise knock-in mouse model. METHODS AND RESULTS: A novel LGI1 mutation, c.152A>G; p. Asp51Gly, was identified by whole exome sequencing in a Chinese family with ADLTE. The pathomechanism of the mutation was explored by generating Lgi1D51G knock-in mice that precisely phenocopied the epileptic symptoms of human patients. The Lgi1D51G/D51G mice showed spontaneous recurrent generalized seizures and premature death. The Lgi1D51G/+ mice had partial epilepsy, with half of them displaying epileptiform discharges on electroencephalography. They also showed enhanced sensitivity to the convulsant agent pentylenetetrazole. Mechanistically, the secretion of Lgi1 was impaired in the brain of the D51G knock-in mice and the protein level was drastically reduced. Moreover, the antiepileptic drugs, carbamazepine, oxcarbazepine, and sodium valproate, could prolong the survival time of Lgi1D51G/D51G mice, and oxcarbazepine appeared to be the most effective. CONCLUSIONS: We identified a novel epilepsy-causing mutation of LGI1 in humans. The Lgi1D51G/+ mouse model, precisely phenocopying epileptic symptoms of human patients, could be a useful tool in future studies on the pathogenesis and potential therapies for epilepsy.

Carrier Screening and Prenatal Diagnosis for Spinal Muscular Atrophy in 13,069 Chinese Pregnant Women.

Spinal muscular atrophy (SMA) is a relatively common, life-shortening, autosomal recessive neuromuscular disease. The carrier frequency of SMA ranges from approximately 0.98% to 2.02%, depending on ethnicity. The American College of Medical Genetics has therefore recommended population screening for SMA carrier status, regardless of race or ethnicity. We performed the largest-scale carrier screening for SMA carriers in mainland China. Carrier screening was offered to 36,470 pregnant women between July 2017 and June 2019, of whom 13,069 women accepted the screening program [35.83%; 95% credibility interval (CI), 35.34%-36.33%]. Copy numbers of exons 7 and 8 in the SMN1 gene were detected by real-time quantitative PCR, and the results were confirmed by multiplex ligation-dependent probe amplification. A total of 231 women were identified as carriers (1.77%; 95% CI, 1.56%-2.01%), indicating a carrier prevalence of approximately 1:56 in the population. After detailed genetic counseling, 207 paternal partners were recalled and tested. Both partners were carriers in 10 couples, of whom prenatal diagnosis was implemented in seven, and one fetus was diagnosed with SMA. Carrier screening could provide couples with informed reproductive choices. Our workflow and experience of carrier screening may facilitate the popularization of SMA carrier screening in mainland China.

Mesenchymal stem cell-derived exosomes carrying microRNA-150 suppresses the proliferation and migration of osteosarcoma cells via targeting IGF2BP1.

BACKGROUND: MicroRNA-150 (miR-150) plays a critical role in varied types of human cancers. In this study, we explored the effect and mechanism of mesenchymal stem cell (MSC)-derived exosomes (exo) carrying miR-150 (MSC-Exo-150) on the proliferation, migration, invasion, and apoptosis of osteosarcoma (OS) cells. METHODS: MiR-150 expression in OS cell lines was assessed by quantitative reverse-transcription PCR (qRT-PCR). MSCs were transfected with cell-miR-67 or has-miR-150, and grouped as MSC-67 or MSC-150. Exosomes were isolated from each group, and separately named MSC-Exo-67, MSC-Exo-150 and MSC-Exo. MTT or flow cytometry assay was used to analyze the proliferation or apoptosis of U2SO and HOS cells, respectively. Wound healing or transwell assay was utilized to examine the migration or invasion of U2SO and HOS cells, respectively. The target relationship of miR-150 and insulin-like growth factor 2 mRNA binding protein 1 (IGF2BP1) was established using StarBase2.0 and verified by dual-luciferase reporter gene analysis. Xenografted tumor model was established in rats to confirm the inhibitory effect of MSC-Exo-150 on the growth of xenografted tumor in vivo. RESULTS: The expression of miR-150 was downregulated in OS cell lines, and significantly higher in MSC-150 cells than that in MSCs. MiR-150 was overexpressed in MSC-Exo-150 group compared with MSC-Exo group. After transfection of MSC-Exo-150 into U2SO and HOS cells, cell viability, mobility and invasion rate were decreased, and the cell apoptosis was increased. MiR-150 targeted IGF2BP1 and IGF2BP1 expression was negatively modulated by miR-150. Overexpression of IGF2BP1 reversed the anti-tumor effect of MSC-Exo-150 on HOS cells. CONCLUSIONS: MSC-Exo-150 inhibited proliferation, migration, invasion, and induced apoptosis of OS cells by targeting IGF2BP1.

A De Novo heterozygous frameshift mutation identified in BCL11B causes neurodevelopmental disorder by whole exome sequencing.

BACKGROUND: Next-generation sequencing has been invaluable to delineate the genetic etiology of neurodevelopmental disorders (NDDs) in recent years. BCL11B, encoding Cys2 His2 zinc finger transcription factor, is essential for the development of immune and neural systems. METHODS: Herein, we describe a Chinese girl presenting craniofacial abnormalities, developmental delay and intellectual disability with speech impairment. Exomes of genes were enriched with the Agilent SureSelect QXT ALL Human Exon V6 kit and sequenced on Illumina Hiseq 2500 platform. RESULTS: After variants filtering and annotation, we identified a de novo heterozygous 11bp frameshift mutation NM_138576.4: c.2190_2200delGGACGCACGAC (p.Thr730Thrfs*151) in exon 4 of BCL11B, which is expected to escape nonsense-mediated mRNA decay and probably result in a truncated protein with lack of the C-terminal DNA-binding zinc-finger domains. CONCLUSION: This is the first report of NDD caused by a BCL11B variant in a Chinese population. The mutation identified in this report broadens the knowledge of mutation spectrum of BCL11B and might help in genetic counseling and reducing reproductive risk.

Effects of FHIT gene on proliferation and apoptosis of osteosarcoma cells.

Regulatory effects of fragile histidine triad (FHIT) gene on proliferation and apoptosis of osteosarcoma cells were studied. The hFOB1.19 and Saos2 cells were routinely cultured, pcDNA3.1-FHIT overexpression vectors carrying FHIT gene fragments and blank pcDNA3.1 vectors were transfected into Saos2 cells, respectively, and the cells were divided into hFOB, Saos2, transfection and no-load transfection groups. After transfection for 48 h, the cells were collected and analyzed. The expression of FHIT messenger ribonucleic acid (mRNA) was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The expression of FHIT protein was detected by western blot analysis. Cell Counting Kit 8 (CCK8) was used to detect cell proliferation, and flow cytometry was used to detect apoptosis. The expression of FHIT mRNA was significantly decreased in Saos2 group compared with that in hFOB group, and the difference was statistically significant (P<0.05). The expression of FHIT mRNA was significantly increased in transfection group compared with that in Saos2 group, and the difference was statistically significant (P<0.05). The expression of FHIT protein was obviously decreased in Saos2 group compared with that in hFOB group, and there was a statistically significant difference (P<0.05). The expression of FHIT protein was obviously increased in transfection group compared with that in Saos2 group, and the difference was statistically significant (P<0.05). Compared with that in the hFOB group, the cell proliferation rate was remarkably increased in Saos2 group, while the apoptosis rate was remarkably decreased, showing statistically significant differences (P<0.05). Compared with those in Saos2 group, the cell proliferation rate was significantly decreased in transfection group, while the apoptosis rate was significantly increased, and the differences were statistically significant (P<0.05). In conclusion, FHIT gene regulates the proliferation and apoptosis of Saos2 osteosarcoma cells, inhibits the proliferation and promotes apoptosis of Saos2 osteosarcoma cells.

Gold Nanoparticle Probe-Assisted Antigen-Counting Chip Using SEM.

Currently, it remains challenging to count protein-biomarker molecules present in a small droplet of biological samples. Herein, we propose a gold nanoparticle (GNP) probe-assisted sandwich-counting strategy that relies on a GNP probe, an antibody-functionalized chip to "count" antigen molecules using a scanning electron microscope. Both standard carcinoembryonic antigen (CEA) and two real CEA-related tumor samples (tumor tissues and serum) were assayed to demonstrate the proof-of-concept of the counting strategy. Results show that our method is excellently correlative with enzyme-linked immuno-sorbent assay (ELISA) that is widely used in clinics for antigen or antibody detection and the limit of detection of our enumeration strategy reaches down to 0.045 ng/mL, which is ∼40 times more sensitive than the conventional ELISA. Therefore, our GNP probe-assisted sandwich-counting strategy has the potential to be used for quantification of protein biomarkers at ultralow concentrations in early tumor specimens and detection of target proteins in much diluted concentrations.

Anatomic locking plates for complex proximal humeral fractures: anatomic neck fractures versus surgical neck fractures.

BACKGROUND: Continued debate exists on the management of displaced 3- or 4-part proximal humeral fractures. Only a few studies have compared the efficacy of proximal humeral locking plates (PHLPs) for treating anatomic neck fractures (ANFs) and surgical neck fractures (SNFs). METHODS: The medical data of 31 consecutive patients with displaced 4-part proximal humeral fractures treated with PHLPs between May 2013 and April 2015 were reviewed retrospectively. We divided the patients into the ANF and SNF groups and assessed the neck-shaft angle (NSA), sum of the screw tip-articular surface distance, and other parameters postoperatively at 3 days and at 12 months using shoulder radiographs. The Constant-Murley scores were assessed at 3 days, 12 months, and last follow-up. RESULTS: The ANF group had a significantly lower mean age and significantly greater mean operative duration, estimated blood loss, and rate of bone grafting. Full or partial osteonecrosis of the humeral head developed in 7 patients and 1 patient in the ANF and SNF groups, respectively. Screw cutout and/or pullout complications occurred in 8 cases in the ANF group but not in the SNF group. In the ANF group, the values for NSA and the sum of the screw tip-articular surface distance changed significantly from 3 days to 12 months postoperatively. There were no significant correlations among the tested parameters. CONCLUSION: ANFs resulted in more complications at a younger age than SNFs. ANF treatment using PHLPs is more prone to a decreased NSA and humeral head osteonecrosis and has poorer clinical outcomes than SNF treatment using PHLPs.

Longitudinal MRI Evaluation of Ischemic Stroke in the Basal Ganglia of a Rhesus Macaque (Macaca mulatta) with Seizures.

An adult rhesus macaque developed seizures after the induction of ischemic stroke. Initially, on the day of surgery, a focal ischemic lesion was present exclusively in the right caudate nucleus. By 48 h after stroke induction, the lesion had extended into the putamen, when a seizure was observed. Our report highlights the temporal changes in infarction of unilateral basal ganglia after acute stroke and the accompanying clinical symptoms. This unusual case may provide additional information regarding the involvement of the basal ganglia in seizures, given that prior case reports and studies usually have not described the temporal and spatial evolution of the lesion before clinical symptoms emerge.

Identification and characterization of a novel 43-bp deletion mutation of the ATP7B gene in a Chinese patient with Wilson's disease: a case report.

BACKGROUND: Wilson's disease (WD) is an autosomal recessive disorder characterized by copper accumulation. ATP7B gene mutations lead to ATP7B protein dysfunction, which in turn causes Wilson's disease. CASE PRESENTATION: We describe a male case of Wilson's disease diagnosed at 10 years after routine biochemical test that showed low serum ceruloplasmin levels and Kayser-Fleischer rings in both corneas. Analysis of the ATP7B gene revealed compound heterozygous mutations in the proband, including the reported c.3517G > A mutation and a novel c.532_574del mutation. The c.532_574del mutation covered a 43-bp region in exon 2, and resulted in a frameshift mutation (p.Leu178PhefsX10). By base sequence analysis, two microhomologies (TCTCA) were observed on both deletion breakpoints in the ATP7B gene. Meanwhile, the presence of some sequence motifs associated with DNA breakage near the deletion region promoted DNA strand break. CONCLUSIONS: By comparison, a replication-based mechanism named fork stalling and template switching/ microhomology-mediated break-induced replication (FoSTeS/MMBIR) was used to explain the formation of this novel deletion mutation.

Rapid screening for Klinefelter syndrome with a simple high-resolution melting assay: a multicenter study.

Klinefelter syndrome (KS) is the set of symptoms that result from the presence of an extra X chromosome in males. Postnatal population-based KS screening will enable timely diagnosis of this common chromosomal disease, providing the opportunity for early intervention and therapy at the time point when they are most effective and may prevent later symptoms or complications. Therefore, through this study, we introduced a simple high-resolution melting (HRM) assay for KS screening and evaluated its clinical sensitivity and specificity in three medical centers using 1373 clinical blood samples. The HRM assay utilized a single primer pair to simultaneously amplify specific regions in zinc finger protein, X-linked (ZFX) and zinc finger protein, Y-linked (ZFY). In cases of KS, the ratios of ZFX/ZFY are altered compared to those in normal males. As a result, the specific melting profiles differ and can be differentiated during data analysis. This HRM assay displayed high analytical specificity over a wide range of template DNA amounts (5 ng-50 ng) and reproducibility, high resolution for detecting KS mosaicism, and high clinical sensitivity (100%) and specificity (98.1%). Moreover, the HRM assay was rapid (2 h per run), inexpensive (0.2 USD per sample), easy to perform and automatic, and compatible with both whole blood samples and dried blood spots. Therefore, this HRM assay is an ideal postnatal population-based KS screening tool that can be used for different age groups.

[Clinical report of testicular hypoplasia combined with 21-hydroxylase deficiency].

OBJECTIVE To investigate the correlation of 21-hydroxylase deficiency (21-OHD) with male testicular dysplasia. METHODS Clinical data of 8 infertile males with congenital adrenal hyperplasia due to 21-OHD was retrospectively analyzed. In addition, potential mutations of the CYP21A2 gene was detected. RESULTS All patients were referred because of azoospermia or severe oligospermia and had small testis with averaged testicular volume of 6.1 mL. Three patients had testicular adrenal rest tumors. Endocrinologic examinations revealed low levels of leutinizing hormone and follicular stimulating hormone, normal or elevated testosterone, elevated progesterone, elevated or normal adrenocoticotropic hormone, and low or normal cortisol. All patients had adrenal cortical hyperplasia, 5 with adrenal adenoma, 1 case associated with bilateral adrenal myelolipoma. All patients were given glucocorticoid replacement therapy for 3 to 6 months, which successfully improved the seminal status of 6 patient and resulted pregnancies in 5 couples. Seven pathogenic mutations of the CYP21A2 gene among the 8 patients. CONCLUSION 21-OHD can cause testicular hypoplasia and spermatogenic failure. Glucocorticoids and operations can obtain good result and improve spermatogenesis. Our results have shown a good genotype/phenotype correlation in these cases. All patients have carried the p.Ile172Asn mutation, which is associated with simple virilizing form.

Combined detection of α-fetoprotein and free ß-human chorionic gonadotropin in screening for trisomy 21 and management of cases in the moderate risk value range.

Down syndrome is the most common cause of prenatal chromosomal abnormalities, and prenatal serum screening is an effective method for decreasing the birth prevalence of children with Down syndrome. The aim of the present study was to observe the effect of duplex screening and investigate the treatment of cases under specific conditions. The medians of free ß-human chorionic gonadotropin (HCG) and α-fetoprotein (AFP) were calculated and compared with those embedded in the 2T software. The detection and false-positive rates were analyzed under different conditions, and the distribution of Down syndrome cases was investigated in different risk ranges. Finally, suitable recommendations for further diagnostic investigation were provided according to the status of each individual. The medians of free ß-HCG and AFP were found to differ from the corresponding medians embedded in the 2T software (P<0.01), and on the basis of a 5% false-positive rate, the detection rate would increase from 63.6 to 67.8% when compared with medians embedded in the 2T software, indicating we should establish our own medians of free ß-HCG and AFP. In addition, residual cases (risk value <1/300) with relevant Down syndrome indications mainly concentrated at risk values between 1/1,000 and 1/300, and partial residual screening cases were verified through diverse methods. These findings indicated that different laboratories should establish their own medians; furthermore, what is classed as moderate risk is extremely important in screening for Down syndrome and reasonable recommendations may be offered under different conditions.

Peptidomic Analysis of Fetal Heart Tissue for Identification of Endogenous Peptides Involved in Tetralogy of Fallot.

Tetralogy of fallot (TOF) is one of the most prevalent types of congenital heart diseases. As a category of bioactive molecules, peptides have been proved to participate in various biological processes. However, the role of endogenous peptides in the pathogenesis of TOF has not been studied. In this study, we performed a comparative peptidomic profile in the fetal heart of TOF and the control group for the first time by liquid chromatography-tandem mass spectrometry. Our data demonstrated that a total of 201 peptides derived from 176 precursor proteins were differentially expressed in the heart tissues of TOF fetuses compared with normal controls, including 41 upregulated peptides and 160 downregulated peptides. After analyzing the characteristics of these differentially expressed peptides and their precursor proteins, we found that these peptides were potentially involved in different biological processes, especially cardiogenesis and congenital anomaly of the cardiovascular system. Interestingly, we detected several extracellular matrix-derived peptides involved in our differentially expressed peptidomic profile. In summary, our study constructed a comparative peptidomic profile from the heart tissues of TOF fetuses and normal controls, and it identified a series of peptides that could potentially participate in heart development and TOF formation. The emergence of our peptidomics study indicated a new perspective to explore the pathogenesis of abnormal heart morphology, especially TOF.

Generation of MERRF patient-derived induced pluripotent stem cell line iMERRF-C7.

Human iPSC line iMERRF-C7 was generated from PBMCs of a patient with mitochondrial disorder MERRF. Using Sendai virus, the reprogramming factors Oct3/4, Sox2, Klf4, and cMyc were delivered non-integratively. The resulting iPSCs expressed pluripotency markers, could differentiate into the three germ layers in vivo, had normal genomic structure, and retained the disease-causing m.8344 mutation with similar heteroplasmic level.

[Detection of TSC1/TSC2 gene mutations among patients with tuberous sclerosis complex by Ion Torrent semiconductor sequencing].

OBJECTIVE: To develop and validate a method for mutation screening and prenatal diagnosis of TSC1/TSC2 mutations among patients with tuberous sclerosis complex (TSC) by Ion Torrent semiconductor sequencing. METHODS: Potential mutations of SC1/TSC2 gene was detected in 2 TSC families and 1 sporadic TSC patient using an Ion Torrent PGM sequencer. Candidate variants were validated by Sanger sequencing. The corresponding site of TSC2 in the fetus of family 2 was also detected with Sanger sequencing. RESULTS: Ion Torrent semiconductor sequencing has identified a probably pathogenic TSC2 mutation (c.311-312insGCTG) in the patient from family 1, and a probably pathogenic TSC2 mutation (c.1790A>G) in the patient of family 2. CONCLUSION: Targeted Ion Torrent PGM sequencing is an accurate and efficient method to detect TSC1/TSC2 mutations in TSC.

[Mutation screening and prenatal diagnosis of methylmalonic academia in a Chinese pedigree by Ion Torrent semiconductor sequencing].

OBJECTIVE: To identify pathogenic mutations in a Chinese pedigree affected with methylmalonic academia for genetic counseling and prenatal diagnosis. METHODS: Molecular analysis of the MUT, MMACHC, MMAA and MMAB genes was performed for the proband with methylmalonic academia by Ion Torrent semiconductor sequencing. Candidate mutations were validated by Sanger sequencing. The couple was offered prenatal diagnosis via analyzing of the fetal DNA through amniocentesis. RESULTS: The proband was found to be compound heterozygous for c.609G>A (p.Trp203X) and c.658-660del AAG (p.Lys220del) mutations, which were inherited respectively from each of his parents. Prenatal diagnosis showed that the fetus has inherited two wild-type parental alleles. CONCLUSION: The targeted Ion Torrent PGM sequencing has detected pathogenic mutations in the Chinese pedigree affected with methylmalonic academia, which has provided molecular evidence for clinical diagnosis, genetic counseling and prenatal diagnosis for the family.