A novel MED12 pathogenic variant in a female fetus with facial cleft and cardiac defects identified in the first trimester.

Trio exome sequencing was performed on a female fetus with an increased nuchal translucency, along with nasal bone hypoplasia, suspected cleft palate and abnormal outflow tract of the heart. A de novo heterozygous variant c.5500_5507del, p.(Tyr1834Argfs × 58) in the MED12 gene was detected. Loss-of-function variants in MED12 in females are associated with Hardikar syndrome (HS). A follow-up ultrasound at 15+5 weeks of gestation identified multiple fetal anomalies including bilateral cleft lip and palate, diaphragmatic hernia, atrioventricular septal defect, persistent truncus arteriosus, and bilateral renal pelvis dilation. Fetal autopsy confirmed the prenatal sonographic findings, and the MED12 variant was discussed by our multidisciplinary team to be the cause of fetal anomalies. Our case is the first prenatal one in which HS was diagnosed due to first trimester structural malformations. This case report presents another example of early identification of a major anomaly which allows earlier genetic diagnosis and more time for clinical management.

Phenotypic and genotypic analysis of 11 fetal cases with Bardet-Biedl syndrome.

OBJECTIVE: To present the prenatal sonographic features and genomic spectrum of pregnancies with fetal Bardet-Biedl syndrome (BBS). METHODS: This was a retrospective study of 11 cases with BBS diagnosed by prenatal ultrasound and confirmed by genetic testing. Clinical and laboratory data were collected and reviewed for these cases, including maternal demographics, prenatal sonographic findings, molecular testing sequencing results, and pregnancy outcomes. RESULTS: All cases had unremarkable first-trimester ultrasound scans without reporting limb malformations. All had second-trimester abnormal ultrasounds: postaxial polydactyly in nine cases (9/11), renal abnormalities in seven (7/11), reduced amniotic fluid volume in two (2/11), central nervous system anomalies in two (2/11), and ascites in three (3/11). Ten fetuses presented with at least two-system anomalies, and one (Case 11) presented with only postaxial polydactyly. Variants were detected in five genes, including BBS2, ARL6/BBS3, BBS7, CEP290/BBS14 and IFT74/BBS22. Ten pregnancies were terminated in the second trimester, while one continued to term. CONCLUSION: Enlarged hyperechogenic kidneys and postaxial polydactyly are the two most common sonographic features of fetal BBS. Prenatal diagnosis of BBS can be done with ultrasound and genetic testing although the diagnosis may be made in the second trimester.

Fetal Phenotype of CHARGE Syndrome with a Molecular Confirmation: A Series of 13 Cases.

INTRODUCTION: CHARGE syndrome is an autosomal dominant genetic disorder with known pattern of features. The aim of the study was to present the fetal features of CHARGE syndrome to gain awareness that the antenatal characteristics can be very nonspecific. CASE PRESENTATION: This was a retrospective study of 13 cases with CHARGE syndrome diagnosed by prenatal or postnatal genetic testing and physical examination. Two (15.4%; 2/13) had normal ultrasound scans during pregnancy. One (7.7%; 1/13) with first-trimester cystic hygroma presented intrauterine fetal demise at 16 weeks gestation. The remaining 10 (76.9%; 10/13) cases had abnormal ultrasound features in utero; among these, 1 had an increased nuchal translucency in the first trimester, 5 had second-trimester abnormal ultrasounds including micrognathia, cardiac defects, and facial defects, and 4 third-trimester abnormal ultrasounds including micrognathia, isolated fetal growth restriction, and polyhydramnios. Among the 11 cases with abnormal prenatal ultrasound scans, no fetus could reach the diagnostic criteria of CHARGE syndrome if only based on the results of ultrasound. However, the diagnosis was made in all cases when CHD7 defects were detected. DISCUSSION/CONCLUSION: The CHARGE syndrome presents non-specific abnormal ultrasound markers in utero. Exome sequencing in the genetic workup will aid in prenatal diagnosis of this syndrome.

Early Onset of Severe Anemia Caused by Hb Calgary (HBB: C.194G > T): Another Case Report.

Unstable hemoglobin (Hb) variants are a rare cause of congenital hemolytic anemia. We describe a Chinese girl who presented with transfusion-dependent anemia in early infancy. Her diagnosis of Hb Calgary [ß64(E8)Gly > Val; HBB:c.194G > T] was not made until molecular testing was performed at the age of 5 years. Our case highlights the importance of early genetic testing in order to make the diagnosis, which may not only be useful for patient management and family counseling, but also for avoiding further unnecessary investigative attempts.

A 6-Year Follow-up of a Chinese Child with Homozygous ß0-Thalaasemia and a Heterozygous KLF1 Mutation.

Patients with the genotype of ß0/ß0 for ß-thalassemia (ß-thal) usually behave as ß-thal major (ß-TM) phenotype which is transfusion-dependent. The pathophysiology of ß-thal is the imbalance between α/ß-globin chains. The degree of α/ß-globin imbalance can be reduced by the more effective synthesis of γ-globin chains, and increased Hb F levels, modifying clinical severity of ß-TM. We report a Chinese child who had homozygous ß0-thal and a heterozygous KLF1 mutation. The patient had a moderate anemia since 6 months old, keeping a baseline Hb value of 8.0-9.0 g/dL. She had normal development except for a short stature (3rd percentile) until 6 years old, when splenomegaly and facial bone deformities occurred. Although genetic alteration of KLF1 expression in ß0/ß0 patients can result in some degree of disease alleviation, our case shows that it is insufficient to ameliorate satisfactorily the presentation. This point should be borne in mind for physicians who provide the genetic counseling and prenatal diagnosis to at-risk families.

Prenatal Diagnosis of Oral Teratoma by Ultrasound.

A pregnant woman had a normal second-trimester anatomic survey at 22 weeks gestation. She was revealed to have a fetal oral mass with polyhydramnios and invisible stomach bubble by ultrasound at 28 weeks. A 50 mm × 36 mm × 42 mm, solid mass was found in the fetal mouth, filling the entire oral cavity. Fetal magnetic resonance imaging showed a homogeneous solid mass in the oral cavity compressing the hypopharynx. At 33 weeks, preterm labor occurred because of the continuation of increased amniotic fluid volume, and a female infant was vaginally delivered. The infant died shortly after tracheal intubation attempt failed. Autopsy confirmed the prenatal sonographic finding. The final pathologic diagnosis was oral immature teratoma. Our study indicates that although oral teratomas are rare, they are readily apparent at prenatal sonographic examinations. Respiratory compromise is the frequent complication of oral teratomas, which is associated with high perinatal mortality.

High accuracy of single-molecule real-time sequencing in detecting a rare α-globin fusion gene in carrier screening population.

INTRODUCTION: The α-globin fusion gene between the HBA2 and HBAP1 genes becomes clinically important in thalassemia screening because this fusion gene can cause severe hemoglobin (Hb) H disease when combining with α0 -thalassemia (α0 -thal). Due to its uncommon rearrangement in the α gene cluster without dosage changes, this fusion gene is undetectable by common molecular testing approaches used for α-thal diagnosis. METHODS: In this study, we used the single-molecule real-time (SMRT) sequencing technique to detect this fusion gene in 23 carriers identified by next-generation sequencing (NGS) among 16,504 screened individuals. Five primers for α and ß thalassemia were utilized. RESULTS: According to the NGS results, the 23 carriers include 14 pure heterozygotes, eight compound heterozygotes with common α-thal alleles, and one homozygote. By using SMRT, the fusion mutant was successfully detected in all 23 carriers. Furthermore, SMRT corrected the diagnosis in two "pure" heterozygotes: one was compound heterozygote with anti-3.7 triplication, and the other was homozygote. CONCLUSION: Our results indicate that SMRT is a superior method compared to NGS in detecting the α fusion gene, attributing to its efficient, accurate, and one-step properties.

Application of real-time PCR-based multicolor melting curve with automatic analysis system in pregestational and prenatal thalassemia diagnoses.

BACKGROUND: To evaluate the value of the real-time PCR-based multicolor melting curve analysis (MMCA) with an automatic analysis system used in a mass thalassemia screening and prenatal diagnosis program. METHODS: A total of 18,912 peripheral blood samples from 9456 couples and 1150 prenatal samples were detected by MMCA assay. All prenatal samples were also tested by a conventional method. Samples with unknown melting peaks, unusual peak height ratios between a wild allele and a mutant allele, or a discordant phenotype-genotype match were further studied by using multiplex ligation-dependent probe amplification (MLPA) or Sanger sequencing. All MMCA results were automatically analyzed and manually checked. The consistency between MMCA assay and conventional methods among prenatal samples was investigated. RESULTS: Except for initiation codon (T > G) (HBB:c.2T > G), all genotypes of thalassemia inside the scope of conventional methods were detected by MMCA assay. Additionally, 27 carriers with 10 rare HBB variants, 13 with α fusion gene, 1 with a rare deletion in α globin gene, and 1 with rare HBA variant were detected by using MMCA assay. CONCLUSION: MMCA can be an alternative approach used in routine thalassemia carrier screening and prenatal diagnosis for its high throughput, sufficient stability, low cost, and easy operation.

Prenatal diagnosis of autosomal recessive Noonan syndrome associated with biallelic LZTR1 variants presented with thick nuchal translucency and cardiac abnormalities.

Noonan syndrome (NS) is a common clinical variable disease characterized by a number of features, mainly including congenital heart defects, short stature, and a variable degree of developmental delay. This disorder is transmitted mostly in an autosomal dominant manner and is genetically heterogeneous. We report three prenatal cases of LZTR1-related recessive NS. One case had a recurrent cystic hygroma at 13 weeks gestation and the pregnancy was terminated. Two cases had an increased nuchal translucency at 12 weeks' gestation, but a normal second trimester ultrasound; both presented with hypertrophic cardiomyopathy in the third trimester. The two infants were diagnosed with NS after birth. All of the three cases had invasive genetic investigations during pregnancy, and trio exome sequencing revealed biallelic likely pathogenic or pathogenic LZTR1 variants in the fetuses. All parents were LZTR1 variant carriers. Our report further strengthens the association of LZTR1 with an autosomal recessive form of NS. The affected fetuses are more likely to have cardiac anomalies. Clarification of molecular diagnosis has important implications in these families because they carry a 25% recurrence risk.

Fetal Hemoglobin H Hydrops Fetalis: Another Three Case Reports.

We report three cases of fetalis hydrops associated with nondeletional α-thalassemia. Two cases were caused by hemoglobin (Hb) H-Quong Sz disease, and one caused by homozygous Hb Constant Spring. Fetal hydrops occurred in the late second trimester in all three cases. Our study indicates that for pregnancies at risk for fetal nondeletional Hb H disease, strict ultrasound follow-up is particularly important. Even without techniques of intrauterine transfusion treatment, early prenatal diagnosis can enable parents to make timely decisions.

ß-Thalassemia Trait Caused by SUPT5H Defects: Another Case Report.

We identified a novel mutation in the SUPT5H gene in a Chinese female who presented with a ß-thalassemia trait. The substitution of c.193C > T (p.Arg65*) leads to a premature stop codon on residue 65 and could be associated with haploinsufficiency. This variant was inherited from the mother who also had the asymptomatic phenotype of ß-thalassemia trait. Our case further supports the role of SUPT5H as a potential ß-globin chain production-modulating gene.

Fetal Rhabdomyoma Leads to Family Diagnosis of Tuberous Sclerosis Complex.

Tuberous sclerosis complex (TSC) is a multisystem genetic disorder characterized by the growth of numerous noncancerous tumors in many parts of the body. It is highly variable in clinical presentations, including a wide range of cognitive, behavioral, and psychiatric manifestations. Of all the possible manifestations, cognitive and behavioral problems are the greatest concern to parents and physicians. In this study, two fetuses were identified to have rhabdomyomas by prenatal ultrasound. Carefully inquired familial medical history revealed other symptoms of TSC such as skin lesions or psychiatric problems in family members in the two families. Both fetuses and family members with positive clinical symptoms were confirmed to carry a familial TSC2 variant. Our study indicates that fetal echocardiography is not just the evaluation of the fetal heart. When fetal cardiac rhabdomyomas are diagnosed, a full family medical history and clinical assessment for TSC in family members should be undertaken.

Megacystis in the First Trimester as an Unreported Sonographic Finding of Alveolar Capillary Dysplasia with Misalignment of Pulmonary Veins Confirmed by Whole-exome Sequencing.

A pregnant woman was revealed to have fetal univentricular heart and megacystis by a routine first-trimester ultrasound. Chorionic villus sampling with the use of karyotyping and microarray found no causative etiologies. A further investigation with whole-exome sequencing (WES) demonstrated a FOXF1 variant. Autopsy confirmed the prenatal findings, and a histological study of the lungs showed the characteristic features of alveolar capillary dysplasia with misalignment of pulmonary veins (ACDMPV). This study indicates that although ultrasound itself has no ability of the identification of pulmonary histological malformations associated with ACDMPV, the early markers of univentricular heart and megacystis might alert clinicians to consider this genetic disorder which is facilitated considerably by the increasingly used WES in prenatal diagnosis.

Adducted Thumb in the First Trimester of Pregnancy: An Early Clue to Prenatal Diagnosis of L1 Syndrome.

A pregnant woman was revealed to have an unusual position of the fetal hand by a routine 12-week ultrasound. Bilateral adducted thumbs and a male phenotype were confirmed by another ultrasound at 14 weeks' gestation. A structural survey at 18 weeks revealed fetal hydrocephalus with severe bilateral ventriculomegaly. The pregnancy was terminated, and postnatal examination with trio exome sequencing detected a hemizygous deletion (1,511 bp in size) variant of L1CAM gene in the fetus, inherited from the mother. The fetus was diagnosed as L1 syndrome (X-linked hydrocephalus). A family study found that this was a familial mutant allele. This study demonstrates that fetal hand abnormalities can be identified in the first trimester. Adducted thumbs might indicate the maldevelopment of the fetal brain, and therefore, examination of fetal hands and fingers should be integrated into fetal anomaly scans.

Accurate Identification of Breakpoints in a Cryptic Reciprocal Translocation by Whole-Genome Sequencing.

Chromosomal abnormalities are a common cause of spontaneous abortions, but conventional detection methods (karyotype, FISH, and chromosomal microarray [CMA]) have limitations, and many cryptic balanced chromosomal rearrangements are difficult to detect. We describe a couple who experienced a missed abortion, studied by CMA. CMA of the abortion tissue detected a 1.62-Mb duplication at 14q11.2 and a 5.09-Mb deletion at 21q11.2q21.1, while the couple seemed to have a normal karyotype. Combining the results of CMA, whole-genome sequencing (WGS) breakpoint analysis, Sanger sequencing, and FISH, we found that the father was a 46,XY,t(14;21)(q11.2;q21.1) balanced translocation carrier. Our results indicate that WGS is an efficient and accurate approach to map breakpoints of cryptic reciprocal balanced translocations undetectable by standard karyotype.

CFTR Suppresses Neointimal Formation Through Attenuating Proliferation and Migration of Aortic Smooth Muscle Cells.

ABSTRACT: Cystic fibrosis transmembrane conductance regulator (CFTR) plays important roles in arterial functions and the fate of cells. To further understand its function in vascular remodeling, we examined whether CFTR directly regulates platelet-derived growth factor-BB (PDGF-BB)-stimulated vascular smooth muscle cells (VSMCs) proliferation and migration, as well as the balloon injury-induced neointimal formation. The CFTR adenoviral gene delivery was used to evaluate the effects of CFTR on neointimal formation in a rat model of carotid artery balloon injury. The roles of CFTR in PDGF-BB-stimulated VSMC proliferation and migration were detected by mitochondrial tetrazolium assay, wound healing assay, transwell chamber method, western blot, and qPCR. We found that CFTR expression was declined in injured rat carotid arteries, while adenoviral overexpression of CFTR in vivo attenuated neointimal formation in carotid arteries. CFTR overexpression inhibited PDGF-BB-induced VSMC proliferation and migration, whereas CFTR silencing caused the opposite results. Mechanistically, CFTR suppressed the phosphorylation of PDGF receptor ß, serum and glucocorticoid-inducible kinase 1, JNK, p38 and ERK induced by PDGF-BB, and the increased mRNA expression of matrix metalloproteinase-9 and MMP2 induced by PDGF-BB. In conclusion, our results indicated that CFTR may attenuate neointimal formation by suppressing PDGF-BB-induced activation of serum and glucocorticoid-inducible kinase 1 and the JNK/p38/ERK signaling pathway.

Prenatal diagnosis of Coffin-Siris syndrome: What are the fetal features?

OBJECTIVE: To present both our center's and previously reported experience of prenatal diagnosis of Coffin-Siris syndrome (CSS) with regard to the laboratory testing and fetal features of this syndrome. METHODS: This was a retrospective study of eight pregnancies with fetal CSS identified by prenatal or postnatal genetic testing. Clinical and laboratory data were collected and reviewed for these cases, including maternal demographics, prenatal sonographic findings, chromosomal microarray and exome sequencing (ES) results, and pregnancy outcomes. RESULTS: A total of eight cases of fetal CSS based on molecular testing were detected. Two cases presented with an increased nuchal translucency (NT) in the first trimester. The remaining six were identified at the second trimester scan. Agenesis of the corpus callosum (ACC) was the most common sonographic finding, accounting for 5/7 (71.4%) cases in which a second trimester sonogram was performed: four had ACC as an isolated finding, and one had additional features of cerebellar hypoplasia and left congenital diaphragmatic hernia. CONCLUSION: CSS should be included in the differential diagnosis when ACC is found by prenatal ultrasound. Both chromosomal microarray and ES should be options when counseling patients with a structurally anomalous fetus.

Prenatal isolated clubfoot increases the risk for clinically significant exome sequencing results.

OBJECTIVE: To examine the diagnostic yield of exome sequencing (ES) in singleton pregnancies with isolated fetal clubfoot. METHODS: Clinical data from singleton pregnancies with a sonographic diagnosis of isolated clubfoot and ES results between 2018 and 2021 were retrospectively obtained from a single referral medical center. The recorded data include maternal age, gestational age at sonographic diagnosis, the indication for genetic testing, ES results, and pregnancy outcomes. RESULTS: During the study period, 38 fetuses were prenatally diagnosed with isolated clubfoot by ultrasound and underwent ES after the copy number variant analysis was non-diagnostic. Through the trio-ES analysis, pathogenic or likely pathogenic variants were detected in 4 of 38 (10.5%) with the following genes: BRPF1, ANKRD17, FLNA, and KIF1A. All are de novo with three of autosomal dominant inheritance and one of X-linked recessive inheritance. CONCLUSION: Sonographic diagnosis of clubfoot, even isolated, increases the risk for monogenic syndromes. Exome sequencing should be an option for genetic investigation for such pregnancies.

Prenatal exome sequencing in fetuses with callosal anomalies.

OBJECTIVE: We aimed to investigate the value of exome sequencing (ES) in fetuses with callosal anomalies (CA) with or without other structural anomalies, but with normal findings by karyotyping and chromosome microarray analysis (CMA). METHODS: Cases with CA with or without other structural anomalies were screened for eligibility. Fetuses with abnormal karyotyping or CMA results were excluded. We performed ES on DNA samples from eligible fetus-parental trios and identified diagnostic genetic variants based on the ultrasonographic features. RESULTS: A total of 50 eligible fetus-parental trios were successfully analyzed by ES. We found 17 likely pathogenic or pathogenic variants in 14 genes from 17 fetuses, with a total proportion of diagnostic genetic variants equal to 34.0% (17/50). Of the 17 cases with a diagnosis, 10 (29.4%, 10/35) were isolated and 7 (43.8%, 7/15) were non-isolated. Pregnancy outcome data showed that 70.0% (7/10) of the surviving isolated CA fetuses with negative ES results had a good prognosis in early childhood. CONCLUSIONS: Our study used ES prenatally for CA and showed that ES can be used diagnostically to define the molecular defects that underlie unexplained CA. Most subjects with isolated CA with negative results for genetic causes will have a favorable prognosis in early childhood.

Prenatal Phenotype of Kabuki Syndrome: Seven Case Series.

INTRODUCTION: Kabuki syndrome (KS) is a multiple congenital anomaly syndrome with characterized facial features. The aim of study was to report on prenatal sonographic findings associated with KS in 7 Chinese families. CASE PRESENTATION: During the study period, 7 families of KS were diagnosed. Variants of KMT2D were detected in 4 cases, and variants of KDM6A in 3 cases. For cases with KMT2D variants, cleft palate was the only finding on second-trimester ultrasound in 2 cases. One case presented with polyhydramnios in late third trimester. One case showed ventricular septal defect and renal anomaly at 22 weeks gestation. For cases with KDM6A variants, one was detected at 22 weeks to have coarctation of the aorta. One presented with third-trimester intrauterine growth restriction. The other with hypoplastic left heart had a maternal KDM6A variant c.1227_1228del. Further family study showed that this variant was also present in the healthy maternal mother, but not in the healthy maternal father and two maternal brothers. The two female carriers were healthy. DISCUSSION/CONCLUSION: Although there is no specific ultrasound feature which has both high sensitivity and high positive predictive value for KS, this disorder should be considered as a differential diagnosis in fetuses with congenital anomalies including polyhydramnios with normal karyotyping/microarray analysis.