PLPPR4 haploinsufficiency causes neurodevelopmental disorders by disrupting synaptic plasticity via mTOR signalling.

Phospholipid phosphatase related 4 (PLPPR4), a neuron-specific membrane protein located at the postsynaptic density of glutamatergic synapses, is a putative regulator of neuronal plasticity. However, PLPPR4 dysfunction has not been linked to genetic disorders. In this study, we report three unrelated patients with intellectual disability (ID) or autism spectrum disorder (ASD) who harbour a de novo heterozygous copy number loss of PLPPR4 in 1p21.2p21.3, a heterozygous nonsense mutation in PLPPR4 (NM_014839, c.4C > T, p.Gln2*) and a homozygous splice mutation in PLPPR4 (NM_014839: c.408 + 2 T > C), respectively. Bionano single-molecule optical mapping confirmed PLPPR4 deletion contains no additional pathogenic genes. Our results suggested that the loss of function of PLPPR4 is associated with neurodevelopmental disorders. To test the pathogenesis of PLPPR4, peripheral blood mononuclear cells obtained from the patient with heterozygous deletion of PLPPR4 were induced to specific iPSCs (CHWi001-A) and then differentiated into neurons. The neurons carrying the deletion of PLPPR4 displayed the reduced density of dendritic protrusions, shorter neurites and reduced axon length, suggesting the causal role of PLPPR4 in neurodevelopmental disorders. As the mTOR signalling pathway was essential for regulating the axon maturation and function, we found that mTOR signalling was inhibited with a higher level of p-AKT, p-mTOR and p-ERK1/2, decreased p-PI3K in PLPPR4-iPSCs neurons. Additionally, we found silencing PLPPR4 disturbed the mTOR signalling pathway. Our results suggested PLPPR4 modulates neurodevelopment by affecting the plasticity of neurons via the mTOR signalling pathway.

Glycerol-3-Phosphate Acyltransferase GPAT9 Enhanced Seed Oil Accumulation and Eukaryotic Galactolipid Synthesis in Brassica napus.

Glycerol-3-phosphate acyltransferase GPAT9 catalyzes the first acylation of glycerol-3-phosphate (G3P), a committed step of glycerolipid synthesis in Arabidopsis. The role of GPAT9 in Brassica napus remains to be elucidated. Here, we identified four orthologs of GPAT9 and found that BnaGPAT9 encoded by BnaC01T0014600WE is a predominant isoform and promotes seed oil accumulation and eukaryotic galactolipid synthesis in Brassica napus. BnaGPAT9 is highly expressed in developing seeds and is localized in the endoplasmic reticulum (ER). Ectopic expression of BnaGPAT9 in E. coli and siliques of Brassica napus enhanced phosphatidic acid (PA) production. Overexpression of BnaGPAT9 enhanced seed oil accumulation resulting from increased 18:2-fatty acid. Lipid profiling in developing seeds showed that overexpression of BnaGPAT9 led to decreased phosphatidylcholine (PC) and a corresponding increase in phosphatidylethanolamine (PE), implying that BnaGPAT9 promotes PC flux to storage triacylglycerol (TAG). Furthermore, overexpression of BnaGPAT9 also enhanced eukaryotic galactolipids including monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), with increased 36:6-MGDG and 36:6-DGDG, and decreased 34:6-MGDG in developing seeds. Collectively, these results suggest that ER-localized BnaGPAT9 promotes PA production, thereby enhancing seed oil accumulation and eukaryotic galactolipid biosynthesis in Brassica napus.

Novel compound heterozygous synonymous and missense variants in the MYO7A gene identified by next-generation sequencing in a Chinese family with nonsyndromic hearing loss.

BACKGROUND: Variants in the MYO7A gene are increasingly identified among patients suffering from Usher syndrome type 1B (USH1B). However, such mutations are less commonly detected among patients suffering from nonsyndromic hearing loss (NSHL), including autosomal recessive deafness (DFNB2) and autosomal dominant deafness (DFNA11). This research attempts to clarify the genetic base of DFNB2 in a Chinese family and determine the pathogenicity of the identified mutations. METHOD: Targeted next-generation sequencing (TGS) of 127 known deafness genes was performed for the 14-year-old proband. Then, Sanger sequencing was performed on the available family members. A minigene splicing assay was performed to verify the impact of the novel MYO7A synonymous variant. After performing targeted next-generation sequencing (TGS) of 127 existing hearing loss-related genes in a 14-year-old proband, Sanger sequencing was carried out on the available family members. Then, to confirm the influence of the novel MYO7A synonymous variants, a minigene splicing assay was performed. RESULTS: Two heteroallelic mutants of MYO7A (NM_000260.3) were identified: a maternally inherited synonymous variant c.2904G > A (p.Glu968=) in exon 23 and a paternally inherited missense variant c.5994G > T (p.Trp1998Cys) in exon 44. The in vitro minigene expression indicated that c.2904G > A may result in skipping of exon 23 resulting in a truncated protein. CONCLUSIONS: We reported a novel missense (c.5994G > T) and identified, for the first time, a novel pathogenic synonymous (c.2904G > A) variant within MYO7A in a patient with DFNB2. These findings enrich our understanding of the MYO7A variant spectrum of DFNB2 and can contribute to accurate genetic counseling and diagnosis of NSHL patients.

[Analysis of ARID1B gene variants in two Chinese pedigrees with Coffin-Siris syndrome].

OBJECTIVE: To explore the genetic basis for two Chinese pedigrees affected with Coffin-Siris syndrome (CSS). METHODS: Whole exome sequencing (WES) was carried out for the probands. Candidate variants were verified by Sanger sequencing of the probands and their family members. RESULTS: The two probands were respectively found to harbor a heterozygous c.5467delG (p.Gly1823fs) variant and a heterozygous c.5584delA (p.Lys1862fs) variant of the ARID1B gene, which were both of de novo in origin and unreported previously. Based on the guidelines of American College of Medical Genetics and Genomics, both variants were predicted to be pathogenic (PVS1+PS2+PM2). CONCLUSION: The c.5467delG (p.Gly1823fs) and c.5545delA (p.Lys1849fs) variants of the ARID1B genes probably underlay the CSS in the two probands. Above results have enabled genetic counselling and prenatal diagnosis for the pedigrees.

Localization of nerve entry points and the center of intramuscular nerve-dense regions in the adult pectoralis major and pectoralis minor and its significance in blocking muscle spasticity.

The aims of this study were to localize the body surface position and depth of nerve entry points, and the center of the intramuscular nerve-dense regions of the pectoralis major and pectoralis minor in order to provide guidance for blocking muscle spasticity. Formalin-fixed adult cadavers (66.3 ± 5.2 years) were used. The curved line on the skin from the acromion to the most inferior point of the jugular notch was defined as the horizontal reference line (H). The line from the most inferior point of the jugular notch to the xiphisternal joint was defined as the longitudinal reference line (L). The nerve entry points was anatomically exposed. Sihler's staining, barium sulfate labeling, and computed tomography were employed to determine the projection points (P) on the body surface. The intersection of the longitudinal line through the P point and the H line and the horizontal line through the P point and the L line were recorded as PH and PL , respectively. The projection of the nerve entry points or the center of the intramuscular nerve-dense regions were in the opposite direction across the transverse plane and were recorded as P'. The percentage positions of PH and PL on the H and L lines, as well as the nerve entry points and the center of the intramuscular nerve-dense regions depths, were determined using the Syngo system. The pectoralis major had two nerve entry points, while the pectoralis minor had only one. In addition, two intramuscular nerve-dense regions were found in the pectoralis major, while only one region was found in the pectoralis minor. The PH of the nerve entry points were located at 47.83%, 32.31%, and 34.31%, while the PH of the center of the intramuscular nerve-dense regions were at 41.95%, 55.88%, and 32.58% of line H, respectively. The PL of the nerve entry points were at -9.84%, 36.16%, and 2.44%, while the PL for each of three center of the intramuscular nerve-dense regions was at -3.87%, 25.29%, and -7.13% of line L, respectively. The depth for each of the nerve entry points was at 17.76%, 17.53%, and 25.51% of line P-P'', respectively, and the depth of the center of the intramuscular nerve-dense regions was at 5.23%, 6.75%, and 13.73% of line P-P', respectively. These percentage values are all means. The definition of the surface position and depth of these nerve entry points and center of the intramuscular nerve-dense regions can improve the localization efficiency and efficacy of target blocking for pectoralis major and minor spasticity.

Genetic analysis and prenatal diagnosis of 20 Chinese families with oculocutaneous albinism.

BACKGROUND: Oculocutaneous albinism (OCA) is a group of heterogeneous genetic disorders characterized by abnormal melanin synthesis in the hair, skin, and eyes. OCA exhibits obvious genetic and phenotypic heterogeneity. Molecular diagnosis of causal genes can be of help in the classification of OCA subtypes and the study of OCA pathogenesis． METHODS: In this study, Sanger sequencing and whole exome sequencing were used to genetically diagnose 20 nonconsanguineous Chinese OCA patients. In addition, prenatal diagnosis was provided to six OCA families. RESULTS: Variants of TYR, OCA2, and HPS1 were detected in 85%, 10%, and 5% of affected patients, respectively. A total of 21 distinct variants of these three genes were identified. Exons 1 and 2 were the hotspot regions of the TYR variants, and c.895C > A and c.896G > A were the hotspot variants. We also found seven novel variants: c.731G > A, c.741C > A, c.867C > A, and c.1037-2A > T in TYR, c.695dupT and c.1054A > G in OCA2, and c.9C > A in HPS1. Genetic tests on six fetuses revealed three carrier fetuses, two normal fetuses, and one affected fetus. The follow-up results after birth were consistent with the results of prenatal diagnosis (one fetus terminated during pregnancy was not followed up). CONCLUSIONS: This study expands our understanding of the genotypic spectrum of the Chinese OCA population. The findings indicate that prenatal diagnosis can provide important information for genetic counseling.

The distal arthrogryposis-linked p.R63C variant promotes the stability and nuclear accumulation of TNNT3.

BACKGROUND: Distal arthrogryposis (DA) is comprised of a group of rare developmental disorders in muscle, characterized by multiple congenital contractures of the distal limbs. Fast skeletal muscle troponin-T (TNNT3) protein is abundantly expressed in skeletal muscle and plays an important role in DA. Missense variants in TNNT3 are associated with DA, but few studies have fully clarified its pathogenic role. METHODS: Sanger sequencing was performed in three generation of a Chinese family with DA. To determine how the p.R63C variant contributed to DA, we identified a variant in TNNT3 (NM_006757.4): c.187C>T (p.R63C). And then we investigated the effects of the arginine to cysteine substitution on the distribution pattern and the half-life of TNNT3 protein. RESULTS: The protein levels of TNNT3 in affected family members were 0.8-fold higher than that without the disorder. TNNT3 protein could be degraded by the ubiquitin-proteasome complex, and the p.R63C variant did not change TNNT3 nuclear localization, but significantly prolonged its half-life from 2.5 to 7 h, to promote its accumulation in the nucleus. CONCLUSION: The p.R63C variant increased the stability of TNNT3 and promoted nuclear accumulation, which suggested its role in DA.

The variations in human orphan G protein-coupled receptor QRFPR affect PI3K-AKT-mTOR signaling.

BACKGROUND: QRFPR is a recently identified member of the G protein-coupled receptor and is an orphan receptor for 26Rfa, which plays important role in the regulation of many physiological functions. METHODS: Here, we employed whole exome sequencing (WES) to examine the patients with intellectual disability (ID) and difficulty in feeding. We performed SIFT and PolyPhen2 predictions for the variants. The structure model was built from scratch by I-TASSER. Here, results derived from a number of cell-based functional assays, including shRNA experiment, intracellular Ca2+ measurement, the expression of PI3 K-AKT-mTOR, and phosphorylation. The functional effect of QRFPR variants on PI3K-AKT-mTOR signaling was evaluated in vitro transfection experiments. RESULT: Here, we identified two QRFPR variants at c.202 T>C (p.Y68H) and c.1111C>T (p.R371W) in 2 unrelated individuals. Structural analysis revealed that p.Y68H and p.R371W variants may affect the side chain structure of adjacent amino acids causing reduced binding of QRFPR to 26Rfa. The results show that QRFPR stimulated by 26Rfa leading to the transient rise of intracellular Ca2+ . The QRFPR variations p.Y68H and p.R371 W can reduce the mobilization of intracellular Ca2+ . The phosphorylation levels of the PI3K, Akt, and mTOR were significantly up- or downregulated by QRFPR overexpression or silencing, respectively. The QRFPR variations inhibited PI3K-AKT-mTOR signaling, resulting in downregulation of p-mTOR. CONCLUSIONS: Our findings suggest that QRFPR acts as important role in neurodevelopment, and the effects of QRFPR are likely to be mediated by the Ca2+ -dependent PI3K-AKT-mTOR pathways. Importantly, these findings provide a foundation for future elucidation of GPCR-mediated signaling and the physiological implications.

Expression of AhATL1, an ABA Transport Factor Gene from Peanut, Is Affected by Altered Memory Gene Expression Patterns and Increased Tolerance to Drought Stress in Arabidopsis.

Arachis hypogaea abscisic acid transporter like-1 (AhATL1) modulates abscisic acid (ABA) sensitivity by specifically influencing the importing of ABA into cells, and is a key player in plant stress responses. However, there is limited information on ABA transporters in crops. In this study, we found that the level of AhATL1 expression and AhATL1 distribution increased more rapidly in the second drought (D2) compared with in the first drought (D1). Compared with the first recovery (R1), the AhATL1 expression level and ABA content remained at a higher level during the second recovery (R2). The heterologous overexpression of AhATL1 in Arabidopsis changed the expression pattern of certain memory genes and changed the post response gene type into the memory gene type. Regarding the proline and water content of Col (Arabidopsis thaliana L. Heynh., Col-0), atabcg22, and AhATL1-OX during drought training, the second drought (D2) was more severe than the first drought (D1), which was more conducive to maintaining the cell osmotic balance and resisting drought. In summary, drought stress memory resulted in a rapid increase in the AhATL1 expression and AhATL1 distribution level, and then raised the endogenous ABA content and changed the post response gene type into the memory gene type, which enhanced the drought resistance and recovery ability.

[Analysis of genetic variation for a child affected with congenital insensitivity to pain with anhidrosis and albinism by whole genome sequencing].

OBJECTIVE: To explore the genetic variation of a Chinese family affected with congenital insensitivity to pain with anhidrosis and albinism. METHODS: Whole exome sequencing (WES) was carried out to screen potential variants within genomic DNA extracted from the proband and his parents. Whole genome sequencing (WGS) was applied when variants were not found completely. Suspected variants were validated by Sanger sequencing. RESULTS: WES has identified a heterozygous c.1729G>C (p.G577R) variant of NTRK1 gene and two heterozygous variants of OCA2 gene, namely c.1363A>G (p.R455G) and c.1182+1G>A. WGS has identified two additional heterozygous variants c.(851-798C>T; 851-794C>G) in deep intronic regions of the NTRK1 gene. CONCLUSION: The compound heterozygous variants of the NTRK1 gene probably underlay the congenital insensitivity to pain with anhidrosis. And the compound heterozygous variants of the OCA2 gene probably underlay the albinism in the proband. In the case where no variant is detected by WES in the coding region, WGS should be considered to screen potential variants in the whole genome.

Koala retrovirus diversity, transmissibility, and disease associations.

BACKGROUND: Koalas are infected with the koala retrovirus (KoRV) that exists as exogenous or endogenous viruses. KoRV is genetically diverse with co-infection with up to ten envelope subtypes (A-J) possible; KoRV-A is the prototype endogenous form. KoRV-B, first found in a small number of koalas with an increased leukemia prevalence at one US zoo, has been associated with other cancers and increased chlamydial disease. To better understand the molecular epidemiology of KoRV variants and the effect of increased viral loads (VLs) on transmissibility and pathogenicity we developed subtype-specific quantitative PCR (qPCR) assays and tested blood and tissue samples from koalas at US zoos (n = 78), two Australian zoos (n = 27) and wild-caught (n = 21) in Australia. We analyzed PCR results with available clinical, demographic, and pedigree data. RESULTS: All koalas were KoRV-A-infected. A small number of koalas (10.3%) at one US zoo were also infected with non-A subtypes, while a higher non-A subtype prevalence (59.3%) was found in koalas at Australian zoos. Wild koalas from one location were only infected with KoRV-A. We observed a significant association of infection and plasma VLs of non-A subtypes in koalas that died of leukemia/lymphoma and other neoplasias and report cancer diagnoses in KoRV-A-positive animals. Infection and VLs of non-A subtypes was not associated with age or sex. Transmission of non-A subtypes occurred from dam-to-offspring and likely following adult-to-adult contact, but associations with contact type were not evaluated. Brief antiretroviral treatment of one leukemic koala infected with high plasma levels of KoRV-A, -B, and -F did not affect VL or disease progression. CONCLUSIONS: Our results show a significant association of non-A KoRV infection and plasma VLs with leukemia and other cancers. Although we confirm dam-to-offspring transmission of these variants, we also show other routes are possible. Our validated qPCR assays will be useful to further understand KoRV epidemiology and its zoonotic transmission potential for humans exposed to koalas because KoRV can infect human cells.

Plastid Glycerol-3-phosphate Acyltransferase Enhanced Plant Growth and Prokaryotic Glycerolipid Synthesis in Brassica napus.

Plastid-localized glycerol-3-phosphate acyltransferase (ATS1) catalyzes the first-step reaction in glycerolipid assembly through transferring an acyl moiety to glycerol-3-phosphate (G3P) to generate lysophosphatidic acid (LPA), an intermediate in lipid metabolism. The effect of ATS1 overexpression on glycerolipid metabolism and growth remained to be elucidated in plants, particularly oil crop plants. Here, we found that overexpression of BnATS1 from Brassica napus enhanced plant growth and prokaryotic glycerolipid biosynthesis. BnATS1 is localized in chloroplasts and an in vitro assay showed that BnATS1 had acylation activity toward glycerol 3-phosphate to produce LPA. Lipid profiling showed that overexpression of BnATS1 led to increases in multiple glycerolipids including phosphatidylglycerol (PG), monogalactosyldiacylglycerol (MGDG), phosphatidylcholine (PC), and phosphatidylinositol (PI), with increased polyunsaturated fatty acids. Moreover, increased MGDG was attributed to the elevation of 34:6- and 34:5-MGDG, which were derived from the prokaryotic pathway. These results suggest that BnATS1 promotes accumulation of polyunsaturated fatty acids in cellular membranes, thus enhances plant growth under low-temperature conditions in Brassica napus.

[Analysis of TWNK variant in a family affected with Perrault syndrome].

OBJECTIVE: To explore the genetic etiology of two patients with Perrault syndrome (PRLTS) in a family. METHODS: Whole exome sequencing (WES) was carried out to screen potential variants within genomic DNA extracted from the proband. Suspected variants were validated by clinical data and results of Sanger sequencing. RESULTS: WES has identified two heterozygous variants of TWNK gene, namely c.1172G>A (p.Arg391His) and c.1844G>C (p.Gly615Ala). Sanger sequencing confirmed that the c.1172G>A (p.Arg391His), a known pathogenic variant, was derived from her father, while the c.1844G>C (p.Gly615Ala), a novel variant, was derived from her mother. Her brother, who was similarly affected, has carried the same compound heterozygous variants. CONCLUSION: The compound heterozygous variants c.1172G>A (p.Arg391His) and c.1844G>C (p.Gly615Ala) of the TWNK gene probably underlie PRLTS in the sib pair. The above results have facilitated genetic counseling and prenatal diagnosis for the affected family.

Diagnosing malignant pleural effusion using clinical and analytical parameters.

BACKGROUND: Malignant pleural effusion (MPE) is common and diagnosis is often problematic. A cancer ratio (serum lactate dehydrogenases: pleural adenosine deaminase ratio) has been proposed for diagnosing MPE. However, the usefulness of this "cancer ratio" and the clinical-radiological criteria for diagnosing MPE has not been clearly determined to date. The aim of this study was to assess the performance of those parameters in the diagnosis of MPE. METHODS: We analyzed 240 patients including 120 with MPE and 120 with non-MPE (93 tuberculous and 27 parapneumonic). Patients were divided into two groups: MPE and non-MPE (eg, tuberculous and parapneumonic). We constructed two predictive models to assess the probability of MPE: (a) clinical-radiological data only and (b) a combination of clinical-radiological data, the cancer ratio, and the carcinoembryonic antigen (CEA). The performances of the predictive models were assessed using receiver operating characteristic (ROC) curves and by examining the calibration. RESULTS: The area under the ROC curves for model 1 and model 2 were excellent, 0.936 and 0.998, respectively. The overall diagnostic accuracies for model 1 and model 2 were 87.5% and 98.8%, respectively. CONCLUSION: The results confirm that both models achieved a high diagnostic accuracy for MPE; however, model 2 was superior with the addition of its simplicity of use in daily practice. This model should be applied to determine which patients with a pleural effusion of unknown origin would not benefit from further invasive procedures.

[Analysis of MYH3 gene variation and prenatal diagnosis for two pedigrees affected with congenital arthrogryposis].

OBJECTIVE: To explore the genetic etiology of two pedigrees affected with congenital arthrogryposis. METHODS: Whole exome sequencing (WES) was used to screen potential variations in the proband. Suspected variations were analyzed with bioinformatics software and validated by Sanger sequencing. RESULTS: A heterozygous c.1123G>A (p.Glu375Lys) variation was detected in the proband and an affected fetus from pedigree 1, while a de novo heterozygous c.118 G>A (p.Val40Met) variation was detected in an affected fetus from pedigree 2. CONCLUSION: The two heterozygous variations of the MYH3 gene probably underlie the disease in the pedigrees. Above results have facilitated genetic counseling and prenatal diagnosis.

[Analysis of SACS mutation in a family affected with autosomal recessive spastic ataxia of Charlevoix-Saguenay].

OBJECTIVE: To carry out mutation analysis for a Chinese family affected with autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). METHODS: Whole exome sequencing (WES) was used to screen potential mutations within genomic DNA extracted from the proband. Suspected mutation was validated by combining clinical data and results of Sanger sequencing. RESULTS: A homozygous deletional mutation c.3665_3675delGTGCTGTCTTA (p.S1222fs) was found in the proband, for which her parents were both heterozygous carriers. CONCLUSION: WES is capable of detecting mutation underlying this disorder and facilitating genetic counseling and prenatal diagnosis for the affected family. A novel pathogenic mutation of the SACS gene was discovered.

[Variant analysis for a pedigree affected with limb-girdle muscular dystrophy type 2D].

OBJECTIVE: To analyze variant of SGCA gene in a Chinese pedigree affected with limb-girdle muscular dystrophy type 2D with whole exome sequencing (WGS). METHODS: Multiplex ligation-dependent probe amplification (MLPA) was employed to detect large fragment deletion or duplication of the DMD gene. FastTargetTM next generation sequencing was used to detect variants of the DMD gene, and the result was verified by Sanger sequencing. After excluding the diagnosis of DMD for the proband, WGS was applied to test the proband and his parents. Suspected pathogenic variants were validated by Sanger sequencing. RESULTS: No variant, deletion or duplication of the DMD gene was detected. Whole exome sequencing showed that the proband has carried compound heterozygous missense variants c.409G>A (p.Glu137Lys) and c.409G>C (p.Glu137Gln) in exon 5 of the SGCA gene, which were respectively inherited from his mother and father. Neither variant was found in DNA derived from the cord blood sample. CONCLUSION: The c.409G>A (p.Glu137Lys) and c.409G>C (p.Glu137Gln) compound heterozygous missense variants probably underlie the disease in the proband. Above finding has facilitated genetic counseling and prenatal diagnosis for the family.

[Mutation analysis and prenatal diagnosis for 50 pedigrees affected with Duchenne/Becker muscular dystrophy].

OBJECTIVE: To establish individualized prenatal diagnosis program for families affected with Duchenne/Becker muscular dystrophy (DMD/BMD) and different clinical background using a variety of methods. METHODS: Multiplex ligation-dependent probe amplification (MLPA) was performed on 50 patients suspected for DMD/BMD. For single exon deletions of the DMD gene, PCR was used for validating the results. For those without any deletion or duplication, Sanger sequencing was used to screen for DMD gene mutations in the children and their mothers. Prenatal genetic testing was provided to female carriers using chorionic villus, amniocentesis or cord blood samples. To ensure the accuracy of diagnosis, all prenatal specimens were also subjected to linkage analysis. RESULTS: Among the 50 patients with DMD/BMD, 23 harbored large deletions, 11 only had single exon deletions, 10 harbored duplications, and 5 had small scare mutations. No mutation was detected in one family. For 37 women undergoing prenatal diagnosis, 10 fetuses were identified as affected males, 6 were female carriers, while 21 were not found to carry any mutation. Testing of creatine kinase was consistent with the results of prenatal diagnosis. For a patient harboring exon 51 deletion, the same mutation was found in a fetus but not in their mother. The proband and fetus had inherited the same haplotype, which suggested that the mother probably has germline mosaicism for the mutation. CONCLUSION: Application of individualized methods for analyzing pregnant women with different clinical background can minimize the risk for giving birth to further children affected with DMD/BMD.

[Whole exome sequencing analysis for a Chinese pedigree affected with X-Linked intellectual disability].

OBJECTIVE: To explore the clinical features and genetic mutation in a family affected with non-syndrome X-linked intellectual disability (NS-XLID) using whole exome sequencing (WES). METHODS: Multiplex ligation-dependent probe amplification (MLPA) was applied to screen potential mutations of Fragile X syndrome (FXS). Whole exome sequencing (WES) and Sanger sequencing were screen for pathological mutations. RESULTS: FXS was excluded by MLPA analysis. WES has discovered in the proband an ARX gene mutation c.88G>T, which was confirmed by Sanger sequencing. Combining his clinical phenotype with information from the OMIM database, it was inferred that the ARX mutation probably underlies the NS-XLID in the proband. The same mutation was found in his mother and two uncles but not in his father and sister. CONCLUSION: WES is capable of revealing the mutation underlying NS-XLID and can facilitate genetic counseling for the affected families.

[Clearance of free fetal DNA after delivery of fetuses carrying chromosomal aneuploidies].

OBJECTIVE: To explore the rules for free fetal DNA clearance after delivery of fetuses carrying chromosomal aneuploidies. METHODS: For 10 women carrying 18-to-25-gestation-week singletons confirmed to have chromosomal abnormalities by amniotic karyotyping, 5 mL of peripheral venous blood was drawn respectively before and 15 minutes, 30 minutes, 60 minutes, 120 minutes, 3 hours, 6 hours, 9 hours, 12 hours, 24 hours, 48 hours and 72 hours after their elective termination of pregnancies. Free fetal DNA was isolated from the plasma and subjected to high throughput sequencing. RESULTS: Statistical analysis of the sequence information showed that the free DNA of fetuses with trisomy 21 or 18 was rapidly cleared after delivery. The average half-life was approximately 1.24 hours within the first 2 hours after delivery. It was then slowly cleared between 6 and 72 hours, with an average half-life of 11.70 hours. No fetal DNA was detectable 72 hours after delivery. CONCLUSION: Free fetal DNA rapidly decreases after delivery and will completely disappear by 72 hours. Above results may provide a basis for clinical application of the non-invasive detection of chromosomal aneuploidies during prenatal diagnosis.