Antenatal ultrasound features of isolated recurrent copy number variation in 7q11.23 (Williams syndrome and 7q11.23 duplication syndrome).

OBJECTIVE: We aimed to gather fetal cases carrying a 7q11.23 copy number variation (CNV) and collect precise clinical data to broaden knowledge of antenatal features in these syndromes. METHODS: We retrospectively recruited unrelated cases with 7q11.23 deletion, known as Williams-Beuren syndrome (WBS), or 7q11.23 duplication who had prenatal ultrasound findings. We collected laboratory and clinical data, fetal ultrasound, cardiac ultrasound and fetal autopsy reports from 18 prenatal diagnostic centers throughout France. RESULTS: 40 fetuses with WBS were collected and the most common features were intra-uterine growth retardation (IUGR) (70.0%, 28/40), cardiovascular defects (30.0%, 12/40), polyhydramnios (17.5%, 7/40) and protruding tongue (15.0%, 6/40). Fetal autopsy reports were available for 11 cases and were compared with ultrasound prenatal features. Four cases of fetuses with 7q11.23 microduplication were collected and prenatal ultrasound signs were variable and often isolated. CONCLUSION: This work strengthens the fact that 7q11.23 CNVs are associated with a broad spectrum of antenatal presentations. IUGR and cardiovascular defects were the most frequent ultrasound signs. By reporting the biggest series of antenatal WBS, we aim to better delineate distinctive signs in fetuses with 7q11.23 CNVs.

Novel homozygous GLDC variant causing late-onset glycine encephalopathy: A case report and updated review of the literature.

Glycine encephalopathy (MIM #605899) is an autosomal recessive inborn error of metabolism caused by pathogenic variants in three genes GLDC, AMT, GCSH encoding glycine cleavage enzyme system. We report an 8-year-old boy with late-onset glycine encephalopathy who harbors a novel homozygous GLDC likely pathogenic variant c.707G > A p.(Arg236Gln). Polyhydramnios was noted at fetal ultrasound. He displayed global developmental delay, craniofacial dysmorphism, convulsions. Our report expands the phenotypic and genetic spectrum of late-onset nonketotic hyperglycinemia.

AKAP9-Related Channelopathy: Novel Pathogenic Variant and Review of the Literature.

Disease-associated pathogenic variants in the A-Kinase Anchor Protein 9 (AKAP9) (MIM *604001) have been recently identified in patients with autosomal dominant long QT syndrome 11 (MIM #611820), lethal arrhythmia (ventricular fibrillation, polymorphic ventricular tachycardia), Brugada syndrome, and sudden unexpected death. However, AKAP9 sequence variations were rarely reported and AKAP9 was classified as a "disputed evidence" gene to support disease causation due to the insufficient genetic evidence and a limited number of reported AKAP9-mutated patients. Here, we describe a 47-year-old male carrying a novel frameshift AKAP9 pathogenic variant who presented recurrent syncopal attacks and sudden cardiac arrest that required a semi-automatic external defibrillator implant and an electric shock treatment of ventricular arrhythmia. This study provides insight into the mechanism underlying cardiac arrest and confirms that AKAP9 loss-of-function variants predispose to serious, life-threatening ventricular arrhythmias.

Heterozygous deletion of the VEGFC gene in 4q34.3 is associated with Milroy-like lymphedema: First prenatal case report.

Deleterious variants in the vascular endothelial growth factor C (VEGFC) gene have been recently associated with Milroy-like primary lymphedema, an autosomal dominant disorder, characterized mainly by swelling of the lower limbs due to functional impairment of the lymphatic vessels. To date, only 26 patients with congenital lymphedema harboring VEGFC pathogenic variants were documented. Here, we describe the first prenatal case of a fetus with Milroy-like disease. Fetal ultrasound showed bilateral foot swelling. Chromosomal microarray analysis revealed a 137-kb copy number loss in 4q34.3 including only VEGFC gene in the propositus fetus. Segregation analysis showed that the deletion was inherited from the affected mother and grandmother. Taken together, our study highlights the important role of microarray analysis to detect subtle chromosomal imbalances in the prenatal setting and contributes to delineate the fetal phenotype of VEGFC-related primary congenital lymphedema.

Intragenic Deletion of the ZMYND11 Gene in 10p15.3 is Associated with Developmental Delay Phenotype: A Case Report.

Submicroscopic 10p15.3 microdeletions were previously reported to be associated with developmental delay, and the smallest region of overlap of 10p15.3 deletion including DIP2C and ZMYND11 was defined. Moreover, pathogenic ZMYND11 truncating variants were subsequently identified in a cohort of patients with developmental delay. Of interest, patients harboring 10p15.3 microdeletions or pathogenic ZMYND11 truncating variants share similar clinical features including hypotonia, intellectual disability, facial dysmorphisms, speech and motor delays, seizures, and significant behavioral problems. Only 1 patient with whole ZMYND11 gene deletion was recorded, and no intragenic ZMYND11 deletion was reported up to date. Here, we describe a 7-year-old boy with developmental delay, carrying the smallest de novo 10p15.3 microdeletion, harboring the 5'UTR and the first 2 exons of ZMYND11. Taken together, our report contributes to expand the clinical and mutational spectrum of ZMYND11 and confirms haploinsufficiency as the underlying disease mechanism.

Novel interstitial 2q12.3q13 microdeletion predisposes to developmental delay and behavioral problems.

Microarray-based comparative genomic hybridization (aCGH) is being increasingly applied to delineate novel genomic disorders and related syndromes in patients with developmental delay. In this study, detailed clinical and cytogenetic data of three unrelated patients with interstitial 2q12.3q13 microdeletion were described and compared with thirteen 2q12.3q13 microdeletion patients, gathered from the medical literature and public databases. 60 K aCGH analysis revealed three overlapping 2q12.3q13 microdeletions measuring 1.88 Mb in patient 1, 1.25 Mb in patient 2, and 0.41 Mb in patient 3, respectively. Confirmation and segregation studies were performed using fluorescence in situ hybridization (FISH) and quantitative real-time PCR. Variable clinical features of 2q12.3q13 microdeletion including microcephaly, prenatal growth retardation, developmental delay, short stature, behavioral problems, learning difficulties, skeletal anomalies, congenital heart defects, and features of ectodermal dysplasia were observed. The boundaries and sizes of the 2q12.3q13 deletions in the sixteen patients were different, but an overlapping region of 249 kb in 2q12.3 was defined. The SRO (smallest region of overlap) encompasses four genes, including LIMS1, RANBP2, CCDC138, and EDAR. Among these genes, RANBP2 is a strong candidate gene for neurological phenotype and genetic susceptibility to viral infections. To our knowledge, this is the first published report of 2q12.3q13 microdeletion syndrome and our observations strongly suggest that these recurrent CNVs may be a novel risk factor for developmental delay with variable expressivity and incomplete penetrance.

Structural abnormalities of chromosome 8 and fetoplacental discrepancy: A second case report and review of fetal phenotype of 8p inverted duplication deletion syndrome.

We described a new second case of fetoplacental discrepancy involving first trimester prenatal detection of mosaic isochromosome i (8) (q10). A 32-year-old woman underwent chorionic villous sampling because of increased fetal nuchal translucency. Analysis of direct chromosome preparations was performed by R-banding and FISH using subtelomeric, centromeric and whole chromosome painting probes for chromosome 8 showing the presence of an isochromosome 8q with a complex, female mosaic karyotype: mos 46,XX,i (8) (q10)[13]/46,XX,del (8) (p23)[10]. Cytogenetic analysis of cultured CVS showed an interstitial duplication with concomitant terminal deletion of the short arm of chromosome 8: 46,XX,der (8)del (8) (p23)dup (8) (p?)[18]. Array-CGH analysis from cultured trophoblasts and fetal tissues revealed a 6.69 Mb terminal deletion in 8p23.3p23.1 associated with a 31.49 Mb duplication in 8p23.1p11.1. FISH analysis confirmed the 8p inverted duplication deletion syndrome. Moreover, polymorphic DNA marker analysis demonstrated that the derivative chromosome 8 was of maternal origin. FISH analysis of cultured peripheral blood lymphocytes showed that the mother also carried a cryptic paracentric inversion inv (8) (p23). Our report contributes to expand the fetal phenotype of 8p inverted duplication deletion syndrome and also provides further insight into the underlying mechanism of this rare genomic disorder.

Novel compound heterozygous TMEM67 variants in a Vietnamese family with Joubert syndrome: a case report.

BACKGROUND: Joubert syndrome is a genetically heterogeneous autosomal recessive ciliopathy characterized by the combination of hypoplasia/aplasia of the cerebellar vermis, thickened and elongated superior cerebellar peduncles and a deep interpeduncular fossa, known as "molar tooth sign" associated with hypotonia, respiratory control disturbances and abnormal eye movements. To date, pathogenic variants in over 35 genes are known to cause autosomal recessive Joubert Syndrome, while one gene is associated with X-linked recessive inheritance. CASE PRESENTATION: We describe here a non-consanguineous Vietnamese family with Joubert syndrome, a fetus and 10-year-old developmentally delayed boy. Ultrasonography showed ventriculomegaly at 26 + 6 weeks of gestation in the fetus. The 10-year-old-boy was diagnosed with cerebral palsy of unknown origin. Clinical physical examination at the age of 10, he showed clinical features of Joubert syndrome including typical facial dysmorphism, ataxia, severe psychomotor delay, oculomotor apraxia and molar tooth sign on brain MRI. Whole exome sequencing analysis identified a novel compound heterozygous c.725A > G p.Asn242Ser and c.313-3 T > G p.Lys105Valfs*16 TMEM67 variant in the proband and the affected fetus. These two variants were inherited from each parent and confirmed by Sanger sequencing. The variant c.725A > G p.Asn242Ser was previously documented in patients with JS, the novel splice-site c.313-3 T > G p.Lys105Valfs*16 TMEM67 variant produced an aberrant transcript with the loss of four nucleotides of exon 03. CONCLUSION: This study confirms the diagnosis of Joubert syndrome in a Vietnamese family and expands the mutational spectrum of TMEM67 sequence variations. We also highlight the importance of molecular approaches to unravel underlying mechanisms of human genetic disorders. Early precise diagnosis could help provide further accurate genetic counseling for recurrence-risk assessment, future diagnostic option, management as well as treatment guidance for rare disorders.

Clinical characteristics and genetic profiles of young and adult patients with cholestatic liver disease

Background and aims: heterozygous ABCB4, ABCB11 and ATP8B1 sequence variants were previously reported to be associated with low phospholipid-associated cholelithiasis, intrahepatic cholestasis of pregnancy, benign recurrent intrahepatic cholestasis and biliary lithiasis. The present study aimed to identify the presence of sequence variations in genes responsible for Mendelian liver disorders in patients with cholestatic liver disease. Methods: targeted massive parallel sequencing of a panel of genes involved in bile acid homeostasis was performed in 105 young and adult patients with cholestatic liver disease in our laboratory for molecular diagnosis. The effects of novel variants were evaluated using bioinformatics prediction tools and the Protter and Phyre2 software programs were used to create 2D, 3D topology protein modeling. Genotype-phenotype correlation was established according to molecular analysis and clinical records. Results: twenty novel heterozygous ABCB4 sequence variations, one heterozygous ABCB4 large intragenic deletion and only one novel missense variant in ABCB11 and ATP8B1 were identified. Interestingly, heterozygous and homozygous SLC4A2 missense variants were detected in patients with low phospholipid-associated cholelithiasis. Two patients harbored heterozygous GPBAR1 variants. Common variants such as homozygous ABCB11 p.Val444Ala and heterozygous ABCG8 p.Asp19His were also identified in 12 cases. Conclusions: forty-eight variants were identified in five genes including ABCB4, ABCB11, ATP8B1, SLC4A2 and GPBAR1, twenty-five of which were novel. This study expands the phenotypic and mutational spectrum in genes involved in bile acid homeostasis and highlights the genetic and phenotypic heterogeneity in patients with inherited liver disorders

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Clinical characteristics and genetic profiles of young and adult patients with cholestatic liver disease.

BACKGROUND AND AIMS: heterozygous ABCB4, ABCB11 and ATP8B1 sequence variants were previously reported to be associated with low phospholipid-associated cholelithiasis, intrahepatic cholestasis of pregnancy, benign recurrent intrahepatic cholestasis and biliary lithiasis. The present study aimed to identify the presence of sequence variations in genes responsible for Mendelian liver disorders in patients with cholestatic liver disease. METHODS: targeted massive parallel sequencing of a panel of genes involved in bile acid homeostasis was performed in 105 young and adult patients with cholestatic liver disease in our laboratory for molecular diagnosis. The effects of novel variants were evaluated using bioinformatics prediction tools and the Protter and Phyre2 software programs were used to create 2D, 3D topology protein modeling. Genotype-phenotype correlation was established according to molecular analysis and clinical records. RESULTS: twenty novel heterozygous ABCB4 sequence variations, one heterozygous ABCB4 large intragenic deletion and only one novel missense variant in ABCB11 and ATP8B1 were identified. Interestingly, heterozygous and homozygous SLC4A2 missense variants were detected in patients with low phospholipid-associated cholelithiasis. Two patients harbored heterozygous GPBAR1 variants. Common variants such as homozygous ABCB11 p.Val444Ala and heterozygous ABCG8 p.Asp19His were also identified in 12 cases. CONCLUSIONS: forty-eight variants were identified in five genes including ABCB4, ABCB11, ATP8B1, SLC4A2 and GPBAR1, twenty-five of which were novel. This study expands the phenotypic and mutational spectrum in genes involved in bile acid homeostasis and highlights the genetic and phenotypic heterogeneity in patients with inherited liver disorders.

Expanding the mutational spectrum of the ABCB4 gene in inherited adult cholestatic liver disorders with four novel pathogenic variants

Low phospholipid-associated cholelithiasis and intrahepatic cholestasis of pregnancy are two MDR3-related inherited liver disorders caused by biallelic or monoallelic ABCB4 loss-of-function variants. Low phospholipid-associated cholelithiasis is clinically characterized by the early onset of symptomatic cholelithiasis in young adults while intrahepatic cholestasis of pregnancy is a distinct clinical entity associated with adverse fetal outcomes. Of note, patients carrying ABCB4 sequence variations commonly exhibit phenotypic expression over a wide continuum due to environmental and hormonal contributing factors and genetic modifiers. Patients with an early diagnosis of MDR3-related diseases could benefit from ursodeoxycholic acid treatment in order to prevent acute and chronic complications as well as adverse pregnancy outcomes. We herein report five patients with an overlapping phenotype from low phospholipid-associated cholelithiasis to intrahepatic cholestasis of pregnancy, harboring five ABCB4 missense variants, four of which were novel. Our study highlights the phenotypic and genetic heterogeneity of inherited cholestatic liver diseases and also expands the mutation spectrum of ABCB4 sequence variations in adult cholestatic liver diseases

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Expanding the mutational spectrum of the ABCB4 gene in inherited adult cholestatic liver disorders with four novel pathogenic variants.

Low phospholipid-associated cholelithiasis and intrahepatic cholestasis of pregnancy are two MDR3-related inherited liver disorders caused by biallelic or monoallelic ABCB4 loss-of-function variants. Low phospholipid-associated cholelithiasis is clinically characterized by the early onset of symptomatic cholelithiasis in young adults while intrahepatic cholestasis of pregnancy is a distinct clinical entity associated with adverse fetal outcomes. Of note, patients carrying ABCB4 sequence variations commonly exhibit phenotypic expression over a wide continuum due to environmental and hormonal contributing factors and genetic modifiers. Patients with an early diagnosis of MDR3-related diseases could benefit from ursodeoxycholic acid treatment in order to prevent acute and chronic complications as well as adverse pregnancy outcomes. We herein report five patients with an overlapping phenotype from low phospholipid-associated cholelithiasis to intrahepatic cholestasis of pregnancy, harboring five ABCB4 missense variants, four of which were novel. Our study highlights the phenotypic and genetic heterogeneity of inherited cholestatic liver diseases and also expands the mutation spectrum of ABCB4 sequence variations in adult cholestatic liver diseases.

A heterozygous microdeletion of 20q13.13 encompassing ADNP gene in a child with Helsmoortel-van der Aa syndrome.

Helsmoortel-van der Aa (SWI/SNF autism-related or ADNP syndrome) is an autosomal dominant monogenic syndrome caused by de novo variants in the last exon of ADNP gene and no deletions have been documented to date. We report the first case of a 3 years and 10 months old boy exhibiting typical features of ADNP syndrome, including intellectual disability, autistic traits, facial dysmorphism, hyperlaxity, mood disorder, behavioral problems, and severe chronic constipation. 60K Agilent array-comparative genomic hybridization (CGH) identified a heterozygous interstitial microdeletion at 20q13.13 chromosome region, encompassing ADNP and DPM1. Taking into account the clinical phenotype of previously reported cases with ADNP single-point variants, genotype-phenotype correlation in the proband was established and the diagnosis of Helsmoortel-van der Aa syndrome was made. Our report thus confirms that ADNP haploinsufficiency is associated with Helsmoortel-van der Aa syndrome as well as highlights the utility of whole-genome array-CGH for detection of unbalanced submicroscopic chromosomal rearrangements in routine clinical setting in patients with unexplained intellectual disability and/or syndromic autism.

15q24.1 BP4-BP1 microdeletion unmasking paternally inherited functional polymorphisms combined with distal 15q24.2q24.3 duplication in a patient with epilepsy, psychomotor delay, overweight, ventricular arrhythmia.

15q24 microdeletion and microduplication syndromes are genetic disorders caused by non-allelic homologous recombination between low-copy repeats (LCRs) in the 15q24 chromosome region. Individuals with 15q24 microdeletion and microduplication syndromes share a common 1.2 Mb critical interval, spanning from LCR15q24B to LCR15q24C. Patients with 15q24 microdeletion syndrome exhibit distinct dysmorphic features, microcephaly, variable developmental delay, multiples congenital anomalies while individuals with reciprocal 15q24 microduplication syndrome show mild developmental delay, facial dysmorphism associated with skeletal and genital abnormalities. We report the first case of a 10 year-old girl presenting mild developmental delay, psychomotor retardation, epilepsy, ventricular arrhythmia, overweight and idiopathic central precocious puberty. 180K array-CGH analysis identified a 1.38 Mb heterozygous interstitial 15q24.1 BP4-BP1 microdeletion including HCN4 combined with a concomitant 2.6 Mb heterozygous distal 15q24.2q24.3 microduplication. FISH analysis showed that both deletion and duplication occurred de novo in the proband. Of note, both copy number imbalances did not involve the 1.2 Mb minimal deletion/duplication critical interval of the 15q24.1q24.2 chromosome region (74.3-75.5 Mb). Sequencing of candidate genes for epilepsy and obesity showed that the proband was hemizygous for paternal A-at risk allele of BBS4 rs7178130 and NPTN rs7171755 predisposing to obesity, epilepsy and intellectual deficits. Our study highlights the complex interaction of functional polymorphisms and/or genetic variants leading to variable clinical manifestations in patients with submicroscopic chromosomal aberrations.

First prenatal case of proximal 19p13.12 microdeletion syndrome: New insights and new delineation of the syndrome.

Proximal 19p13.12 microdeletion has been rarely reported. Only five postnatal cases with intellectual disability, facial dysmorphism, branchial arch defects and overlapping deletions involving proximal 19p13.12 have been documented. Two critical intervals were previously defined: a 700 kb for branchial arch defects and a 350 kb for hypertrichosis-synophrys-protruding front teeth. We describe the first prenatal case, a fetal death in utero at 39 weeks of gestation. Agilent 180K array-CGH analysis identified a heterozygous interstitial 745 kb deletion at 19p13.12 chromosome region, encompassing both previously reported critical intervals, including at least 6 functionally relevant genes: NOTCH3, SYDE1, AKAP8, AKAP8L, WIZ and BRD4. Quantitative PCR showed that the deletion occurred de novo with a median size of 753 kb. NOTCH3 and SYDE1 were candidate genes for placental pathology whilst AKAP8, AKAP8L, WIZ and BRD4 were highly expressed in the branchial arches. Molecular characterization and sequencing of candidate genes for placental pathology and branchial arch defects were carried out in order to correlate the genotype-phenotype relationship and unravel the underlying mechanism of proximal 19p13.12 microdeletion syndrome. This case also contributes to define the novel critical interval and expand the clinical phenotype spectrum of proximal 19p13.12 microdeletion syndrome.

WAGR syndrome and congenital hypothyroidism in a child with a Mosaic 11p13 deletion.

Wilm's tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome, a rare genetic disorder, is caused by the loss of 11p13 region including PAX6 and WT1. We report novel findings in a 28-month-old boy with aniridia, Wilm's tumor, congenital hypothyroidism, and sublingual thyroid ectopia. He was found to have a mosaic 5.28 Mb interstitial deletion of chromosome 11p13 deleting PAX6 and WT1. In order to clarify the mechanism underlying his thyroid dysgenesis, sequence analysis of candidate thyroid developmental genes was performed. We identified a FOXE1: c.532_537delGCCGCC p.(Ala178_Ala179del) variant that predisposes to thyroid ectopia. Taken together, this is the first report of mosaic 11p13 deletion in association with thyroid dysgenesis. We also propose a model of complex interactions of different genetic variants for this particular phenotype in the present patient.

In vitro culture of Keratinocytes from human umbilical cord blood mesenchymal stem cells: the Saigonese culture.

There have been many attempts to acquire and culture human keratinocytes for clinical purposes including from keratotome slices in media with fetal calf serum (FCS) or pituitary extract (PE), from skin specimens in media with feeder layers, from suction blister epidermal roofs' in serum-free culture and from human umbilical cord blood (hUCB) mesenchymal stem cells (MSCs) in media with skin feeder layers. Conversely this study was designed to investigate whether keratinocytes could be obtained directly from hUCB MSCs in vitro. It is widely established that mesenchymal stem cells from human umbilical cord blood have multipotent capacity and the ability to differentiate into disparate cell lineages hUCB MSCs were directly induced to differentiate into keratinocytes by using a specific medium composed of primary culture medium (PCM) and serum free medium (SFM) in a ratio 1:9 for a period of 7 days and tested by immunostain p63 and K1-K10. Cells thus cultured were positive in both tests, confirming the possibility to directly obtain keratinocytes from MSCs hUCB in vitro.