Prenatal case of Simpson-Golabi-Behmel syndrome with a de novo 370Kb-sized microdeletion of Xq26.2 compassing partial GPC3 gene and review.

BACKGROUND: Simpson-Golabi-Behmel syndrome type 1 (SGBS1) is a rare X-linked recessive disorder characterized by pre- and postnatal overgrowth and a broad spectrum of anomalies including craniofacial dysmorphism, heart defects, renal, and genital anomalies. Due to the ultrasound findings are not pathognomonic for this syndrome, most clinical diagnosis of SGBS1 are made postnatally. METHODS: A pregnant woman with abnormal prenatal sonographic findings was advised to perform molecular diagnosis. Single nucleotide polymorphism array (SNP array) was performed in the fetus, and the result was validated with multiplex ligation-dependent probe amplification (MLPA) and real-time quantitative PCR (qPCR). RESULTS: The prenatal sonographic presented with increased nuchal translucency at 13 gestational weeks, and later at 21 weeks with cleft lip and palate, heart defect, increased amniotic fluid index and over growth. A de novo 370Kb-deletion covering the 5'-UTR and exon 1 of GPC3 gene was detected in the fetus by SNP array, which was subsequently confirmed by MLPA and qPCR. CONCLUSION: The de novo 370Kb hemizygous deletion of 5'-UTR and exon 1 of GPC3 results in the SGBS1 of this Chinese family. Combination of ultrasound and genetics tests helped us effectively to diagnose the prenatal cases of SGBS1. Our findings also enlarge the spectrum of mutations in GPC3 gene.

A GLI3 variant leading to polydactyly in heterozygotes and Pallister-Hall-like syndrome in a homozygote.

Variants in transcriptional activator Gli Kruppel Family Member 3 (GLI3) have been reported to be associated with several phenotypes including Greig cephalopolysyndactyly syndrome (MIM #175700), Pallister-Hall syndrome (PHS) (MIM #146510), postaxial polydactyly types A1 (PAPA1) and B (PAPB) (MIM #174200), and preaxial polydactyly type 4 (MIM #174700). All these disorders follow an autosomal dominant pattern of inheritance. Hypothalamic hamartomas (MIM 241800) is associated with somatic variants in GLI3. We report a related couple with parents having PAPA1 and PAPB, who had a fetus with a phenotype most compatible with PHS. Molecular analyses demonstrated homozygosity for a pathogenic GLI3 variant (c.1927C > T; p. Arg643*) in the fetus and heterozygosity in the parents. The genetic analysis in this family demonstrates that heterozygosity and homozygosity for the same GLI3 variant can cause a different phenotype. Furthermore, the occurrence of Pallister-Hall-like syndrome in a homozygous patient should be taken into account in genetic counseling of families with PAPA1/PAPB.

Maceration determines diagnostic yield of fetal and neonatal whole body post-mortem ultrasound.

OBJECTIVES: To determine factors in nondiagnostic fetal and neonatal post-mortem ultrasound (PMUS) examinations. METHODS: All fetal and neonatal PMUS examinations were included over a 5-year study period (2014-2019). Nondiagnostic image quality by body parts (brain, spine, thorax, cardiac, and abdomen) was recorded and correlated with patient variables. Descriptive statistics and logistic regression analyses were performed to identify significant factors for nondiagnostic studies. RESULTS: Two hundred sixty-five PMUS examinations were included, with median gestational age of 22 weeks (12-42 wk), post-mortem weight of 363 g (16-4033 g), and post-mortem interval of 8 days (0-39 d). Diagnostic imaging quality was achieved for 178/265 (67.2%) studies. It was high for abdominal (263/265, 99.2%), thoracic (264/265, 99.6%), and spine (265/265, 100%) but lower for brain (210/265, 79.2%) and cardiac imaging (213/265, 80.4%). Maceration was the best overall predictor for nondiagnostic imaging quality (P < .0001). Post-mortem fetal weight was positively associated with cardiac (P = .0133) and negatively associated with brain imaging quality (P = .0002). Post-mortem interval was not a significant predictor. CONCLUSIONS: Fetal maceration was the best predictor for nondiagnostic PMUS, particularly for brain and heart. Fetuses with marked maceration and suspected cardiac or brain anomalies should be prioritised for post-mortem MRI.

Quantitative anatomy of the primary ossification center of the radial shaft in human fetuses.

PURPOSE: The medical literature still lacks studies on the size of the radial shaft primary ossification center, thus preventing us from potentially relevant data in diagnosing skeletal dysplasias, i.e., TAR syndrome, VATER syndrome, Holt-Oram syndrome, Fanconi anemia and Edwards syndrome, frequently characterized by disrupted or retarded fetal growth. MATERIALS AND METHODS: The size of the radial shaft primary ossification center in 47 (25 males and 22 females) spontaneously aborted human fetuses aged 17-30 weeks was studied by means of CT, digital image analysis and statistics. RESULTS: With neither sex nor laterality differences, the best-fit growth dynamics for the radial shaft primary ossification center was modeled by the following functions: y = - 10.988 + 1.565 × age ± 0.018 for its length, y = - 2.969 + 0.266 × age ± 0.01 for its proximal transverse diameter, y = - 0.702 + 0.109 × age ± 0.018 for its middle transverse diameter, y = - 2.358 + 0.203 × age ± 0.018 for its distal transverse diameter, y = -189.992 + 11.788 × (age)2 ± 0.018 for its projection surface area, and y = - 798.174 + 51.152 × age ± 0.018 for its volume. CONCLUSIONS: The morphometric characteristics of the radial shaft primary ossification center show neither sex nor bilateral differences. The radial shaft primary ossification center grows proportionately in length, transverse dimensions and volume, and quadratically in its projection surface area. The obtained numerical findings of the radial shaft ossification center are considered age-specific reference of relevance in both the estimation of fetal ages and the diagnostic process of congenital defects.

Potential clinical benefits and limitations of fetal virtopsy using high-field MRI at 7 Tesla versus stereomicroscopic autopsy to assess first trimester fetuses.

OBJECTIVE: The aim of this study was to establish the diagnostic accuracy of high-field magnetic resonance imaging (MRI) at 7 Tesla (T) compared with that of stereomicroscopic autopsy for assessing first trimester fetuses. METHODS: Nine consecutive cases of first trimester fetuses resulting from spontaneous and therapeutic pregnancy termination were considered. The cases were divided into two groups according to gestational age: the Embryo Group with cases of nine to 10 gestational weeks (GWs) and the Fetus Group with cases of 13 GWs. The first group was scanned using three-dimensional fast imaging with steady state precession (3D FISP), and the second group was scanned using a two-dimensional (2D) turbo spin-echo high-resolution T2-weighted imaging (T2 WI) protocol. A radiologist and two embryologists interpreted the images. All cases were evaluated by invasive autopsy, with pathologist blinded to the imaging results. In total, the database included 270 items for evaluation (9 cases × 30 structures/case). RESULTS: The global agreement between fetal high-field virtopsy and microscopic or stereomicroscopic autopsy was evaluated using 225 evaluation items visible by both methods. Overall, using microscopic examination and stereomicroscopic autopsy as the gold standard, fetal high-field virtopsy had a sensitivity of 94.6% [95% CI, 87.2-98.3] and a specificity of 97.6% [95% CI, 95-98.8]. The positive predictive value (PPV) was 93% [95% CI, 85.7-96.6], and the negative predictive value (NPV) was 98.2% [95% CI, 95.7-99.4]. Cohen kappa coefficient of agreement was k = 0.92 [95% CI, 0.82-0.97], and the McNemar test showed p = 1.00. CONCLUSIONS: Virtual autopsy using high-field MRI at 7 T can be considered a safe alternative approach to stereomicroscopic autopsy for the assessment of fetal structural anomalies at the end of the first trimester of pregnancy.

Quantitative anatomy of the primary ossification center in the fetal pubis bone.

PURPOSES: Skeletodysplasiae and hereditary dysostoses constitute a group of over 350 disorders of the skeletal system. Knowledge about development of the pubic primary ossification center may be useful in both determining the fetal stage and maturity, and for detecting congenital disorders. The present study was performed to quantitatively examine the pubic primary ossification center with respect to its linear, planar, and volumetric parameters. MATERIALS AND METHODS: Using methods of computed tomography (CT), digital-image analysis and statistics, the size of the pubic primary ossification center in 33 spontaneously aborted human fetuses (18 males and 15 females) aged 22-30 weeks was studied. RESULTS: With no sex and laterality differences, the best-fit growth dynamics for the pubic primary ossification center was modeled by the following functions: y = - 13.694 + 0.728 × age ± 0.356 for its sagittal diameter, y = - 3.350 + 0.218 × age ± 0.159 for its vertical diameter, y = - 61.415 + 2.828 × age ± 1.519 for its projection surface area, and y = - 65.801 + 3.173 × age ± 2.149 for its volume. CONCLUSIONS: The size of the pubic primary ossification center shows neither sex nor laterality differences. The growth dynamics of the vertical and sagittal diameters, projection surface area, and volume of the pubic ossification centers follow proportionately to fetal age. The obtained numerical findings of the pubic ossification center are considered age-specific reference data with clinical implications in the diagnostics of congenital defects.

Uniparental isodisomy as a cause of recessive Mendelian disease: a diagnostic pitfall with a quick and easy solution in medium/large NGS analyses.

Complete uniparental isodisomy (iUPD)-the presence of two identical chromosomes in an individual that originate from only a single parental homolog-is an underestimated cause of recessive Mendelian disease in humans. Correctly identifying iUPD in an index patient is of enormous consequence to correctly counseling the family/couple, as the recurrence risk for siblings is reduced from 25% to usually <1%. In medium/large-scale NGS analyses, we found that complete iUPD can be rapidly and straightforwardly inferred from a singleton dataset (index patient only) through a simple chromosome- and genotype-filtering step in <1 min. We discuss the opportunities of iUPD detection in medium/large-scale NGS analyses by example of a case of CHRNG-associated multiple pterygium syndrome due to complete maternal iUPD. Using computer simulations for several detection thresholds, we validate and estimate sensitivity, specificity, positive (PPV), and negative predictive values (NPV) of the proposed screening method for reliable detection of complete iUPD. When screening for complete iUPD, our models suggest that a >85% proportion of homozygous calls on a single chromosome with ≥30 sufficiently interspaced called variants results in a sensitivity of 97.9% and specificity of 99.7%. The PPV is 95.1%, the NPV 99.9%. When this threshold is exceeded for a chromosome on which a patient harbors an apparently homozygous disease-associated variant, it should be sufficient cause to discuss iUPD as a plausible or probable mechanism of disease in the genetic analysis report, even when parental segregation has not (yet) been performed.

Quantitative anatomy of the ilium's primary ossification center in the human fetus.

PURPOSE: An understanding of the development of the ilium's primary ossification center may be useful in both determining the fetal stage and maturity, and for detecting congenital disorders. This study was performed to quantitatively examine the ilium's primary ossification center with respect to its linear, planar and volumetric parameters. MATERIALS AND METHODS: Using methods of CT, digital-image analysis and statistics, the size of the ilium's primary ossification center in 42 spontaneously aborted human fetuses of crown-rump length (CRL) ranged from 130 to 265 mm (aged 18-30 weeks) was studied. RESULTS: With no sex and laterality differences, the best fit growth dynamics for the ilium's primary ossification center was modelled by the following functions: y = - 63.138 + 33.413 × ln(CRL) ± 1.609 for its vertical diameter, y = - 59.220 + 31.353 × ln(CRL) ± 1.736 for its transverse diameter, y = - 105.681 + 1.137 × CRL ± 16.035 for its projection surface area, and y = 478.588 + 4.035 × CRL ± 14.332 for its volume. The shape of the ilium's primary ossification center did not change over the study period, because its transverse -to- vertical diameter ratio was stable at the level of 0.94 ± 0.07. Conclusions The size of the ilium's primary ossification center displays neither sex nor laterality differences. The ilium's primary ossification center grows logarithmically with respect to its vertical and transverse diameters, and linearly with respect to its projection surface area and volume. The shape of the ilium's primary ossification center does not change throughout the examined period. The obtained quantitative data of the ilium's primary ossification center is considered normative for respective prenatal weeks and may contribute to the prenatal ultrasound diagnostics of congenital defects.

Postmortem microfocus computed tomography for early gestation fetuses: a validation study against conventional autopsy.

BACKGROUND: Perinatal autopsy provides useful clinical information in up to 40% of cases. However, there is a substantial unmet clinical need with regards to postmortem investigation of early gestation fetal loss for parents for whom standard autopsy is either not available or not acceptable. Parents dislike the invasive nature of autopsy, but current clinical imaging techniques do not provide high-enough imaging resolution in small fetuses. We hypothesized that microfocus computed tomography, which is a rapid high-resolution imaging technique, could give accurate diagnostic imaging after early gestation fetal loss. OBJECTIVE: The objective of the study was to evaluate the diagnostic accuracy of microfocus computed tomography for noninvasive human fetal autopsy for early gestation fetuses, with the use of conventional autopsy as the reference standard. STUDY DESIGN: We compared iodinated whole body microfocus computed tomography in 20 prospectively recruited fetuses (11-21 weeks gestation from 2 centers) with conventional autopsy in a double-blinded manner for a main diagnosis and findings in specific body organs. Fetuses were prepared with 10% formalin/potassium tri-iodide. Images were acquired with a microfocus computed tomography scanner with size-appropriate parameters. Images were evaluated independently by 2 pediatric radiologists, who were blinded to formal perinatal autopsy results, across 40 individual indices to reach consensus. The primary outcome was agreement between microfocus computed tomography and conventional autopsy for overall diagnosis. RESULTS: Postmortem whole body fetal microfocus computed tomography gave noninvasive autopsy in minutes, at a mean resolution of 27µm, with high diagnostic accuracy in fetuses at <22 weeks gestation. Autopsy demonstrated that 13 of 20 fetuses had structural abnormalities, 12 of which were also identified by microfocus computed tomography (92.3%). Overall, microfocus computed tomography agreed with overall autopsy findings in 35 of 38 diagnoses (15 true positive, 18 true negative; sensitivity 93.8% [95% confidence interval, 71.7-98.9%], specificity 100% [95% confidence interval, 82.4-100%]), with 100% agreement for body imaging diagnoses. Furthermore, after removal of nondiagnostic indices, there was agreement for 700 of 718 individual body organ indices that were assessed on microfocus computed tomography and autopsy (agreement, 97.5%; 95% confidence interval, 96.1-98.4%), with no overall differences between fetuses at ≤14 or >14 weeks gestation (agreement, 97.2% and 97.9%, respectively). Within first-trimester fetal loss cases (<14 weeks gestation), microfocus computed tomography analysis yielded significantly fewer nondiagnostic indices than autopsy examination (22/440 vs 48/348, respectively; P<.001). CONCLUSION: Postmortem whole-body fetal microfocus computed tomography gives noninvasive, detailed anatomic examinations that are achieved in minutes at high resolution. Microfocus computed tomography may be preferable to magnetic resonance imaging in early gestation fetuses and may offer an acceptable method of examination after fetal loss for parents who decline invasive autopsy. This will facilitate autopsy and subsequent discussions between medical professionals who are involved in patient care and counselling for future pregnancies.

Quantitative description of the morphology and ossification center in the axial skeleton of 20-week gestation formalin-fixed human fetuses using magnetic resonance images.

OBJECTIVES: Human tissues are usually studied using a series of two-dimensional visualizations of in vivo or cutout specimens. However, there is no precise anatomical description of some of the processes of human fetal development. The purpose of our study is to develop a quantitative description of the normal axial skeleton by means of high-resolution three-dimensional magnetic resonance (MR) images, collected from six normal 20-week-old human fetuses fixed in formaldehyde. METHODS: Fetuses were collected after spontaneous abortion and subsequently fixed with formalin. They were imaged using a 1.5 T MR scanner with an isotropic spatial resolution of 200 µm. The correct tissue discrimination between ossified and cartilaginous bones was confirmed by comparing the images achieved by MR scans and computerized axial tomographies. The vertebral column was segmented out from each image using a specially developed semi-automatic algorithm. RESULTS: Vertebral body dimensions and inter-vertebral distances were larger in the lumbar region, in agreement with the beginning of the ossification process from the thoracolumbar region toward the sacral and cephalic ends. CONCLUSION: In this article, we demonstrate the feasibility of using MR images to study the ossification process in formalin-fixed fetal tissues. A quantitative description of the ossification centers of vertebral bodies and arches is presented.

Benefits of examination by post mortem performed magnetic resonance imaging of foetus: haemorrhage in germinal matrix.

Post mortem magnetic resonance imaging is demonstrated as a supplementary method to classic pathological-anatomical autopsy in determining anomalies of the foetus. Frequently it plays a key role; primarily where the possibilities of performing autopsy are somehow limited (autolysis, ventricular dilatation). Specification of the final diagnosis subsequently enables us to improve prenatal diagnostics, both by means of magnetic resonance imaging and primarily by correlation with the prenatal ultrasound scan; this feedback improves the later method. This case report demonstrated that post mortem magnetic resonance imaging, in contrast with prenatal ultrasound examination, showed extensive haemorrhage in the germinal matrix, and also illustrated indirect symptoms testifying to agenesis of the corpus callosum. Prenatal ultrasound examination showed only hydrocephalus and absence of septum pellucidum. Pathological-anatomical autopsy of the brain was insufficient with regard to advanced autolysis and brain haemorrhage.

Pelizaeus Merzbacher disease: morphological analysis of the vestibulo-cochlear system.

CONCLUSION: In agreement with previously published findings, our results demonstrate that Pelizaeus Merzbacher disease (PMD) does not affect the development and morphology of the peripheral vestibulo-cochlear system. OBJECTIVE: PMD is a consequence of X-linked mutation of the main central nervous system (CNS) myelin protein resulting in a complex neurological syndrome. Otorhinolaryngological symptoms include nystagmus and alterations of auditory-evoked brainstem responses. To date no histopathological analysis of the inner ear has been performed. MATERIALS AND METHODS: The temporal bone morphology of an affected fetus was examined with light microscopy and synchrotron radiation-based micro computed tomography. RESULTS: The regular structure of the vestibulo-cochlear system was shown in this multi-modular analysis.

Radiological-pathological comparison in a case of conjoined gnatho-thoracopagus twins.

BACKGROUND: Conjoined twins may present an extremely wide range of complex congenital malformations. Because of the increasing number of attempts to separate them surgically, profound knowledge is needed of this abnormality spectrum. CASE: Ultrasonographic, radiological (X-ray, computed tomography and magnetic resonance imaging) and pathological findings of gnatho-thoracopagus conjoined twins at 18 weeks of gestation are reported, focusing on clinical topographic correlations. CONCLUSIONS: High-resolution imaging techniques may provide useful information for surgery or autopsy planning of cases with complex congenital malformations.

Schneckenbecken dysplasia in fetus: report of four cases.

Several different types of lethal short-limbed skeletal dysplasia with platyspondylia have been recognized with a different mode of inheritance. Schneckenbecken dysplasia, a very rare lethal osteochondrodysplasia, is included in these entities, with an autosomal recessive mode of inheritance. We describe 4 new Tunisian cases with clinical, radiographic and histopathological features. The fetuses were of consanguineous parents. Prenatal diagnostics of short limbs were carried out on ultrasounds at 20, 22, 23 and 28 weeks of gestation. The radiographic findings were typical, showing especially the small ilia with medial snail-like projection. The chondro-osseous histology of the 4 cases was compatible with the diagnostics demonstrating cartilage anomalies characterized by hypercellularity, hypervascularisation and chondrocytes with central large round nucleus. Schneckenbecken dysplasia should be considered when the phenotype of dwarfism and snail feature of iliac bone associated with histological finding are presented. Frozen fetal samples should be taken in order to look for candidate genes.

Prenatal cortical hyperostosis with COL1A1 gene mutation.

Infantile cortical hyperostosis (Caffey disease) is benign and self-limiting when it presents near or after birth but it is usually lethal when it presents earlier. We present the clinical, ultrasonic, radiographic, and pathologic findings in an instructive case of early onset prenatal cortical hyperostosis. The pregnancy of a 21-year-old woman was medically terminated at 30 weeks of gestation after a diagnosis of severe osteogenesis imperfecta. Prenatal ultrasounds showed short long bones. Postmortem radiographs showed hyperostosis in long bones, ribs and mandible. The affected skeleton showed marked bony sclerosis and ballooning of the diaphyses of the long bones with periosteal sclerosis. A complete autopsy showed characteristic histologic findings of infantile cortical hyperostosis in affected bones. A missense mutation (3040C --> T) in exon 41 the gene encoding the alpha 1 chain of type I collagen was found in fetus pulmonary tissue. Neither the severe form nor the mild form of prenatal cortical hyperostosis were thought to be related to collagen I mutations. Our study indicates that a heterozygous 3040C --> T mutation can also be found in lethal prenatal cortical hyperostosis.

Nasal bone length in human fetuses by X-ray.

BACKGROUND: To construct a normal range for the prenatal nasal bone length (NBL) in Brazilians irrespective to the knowledge of the ethnic genetic background. STUDY DESIGN: We studied 35 human fetuses (20 males, 15 females) ranging from 14 to 22 weeks of gestation. Gestational age (GA), crown-rump length (CRL), foot length (FL) and body mass (BM) were measured. The X-ray of the head lateral view was made with the specimens placed directly on the film and the NBL was measured. The NBL was correlated with the GA, the CRL, the FL, and the BM using log-transformed data and the allometric model log y=log a+b log x. RESULTS: Correlations of the NBL growth with GA, CRL, FL, and BM were positive and significant (P<0.05), but NBL vs. BM showed the smallest R indicating this correlation as of little practical use. No sexual dimorphism in the NBL growth in the second trimester fetuses was observed. The NBL grew with positive allometry relative to GA, CRL and BM, but it was allometrically slightly negative relative to the FL in both genders. The NBL be allometrically positive against GA, CRL and BM means the bone grew with growth rates higher than those indices in the period analyzed, but not against FL. CONCLUSION: NBL could be considered an auxiliary measurement in the assessment of the 2nd trimester fetal development because its strong correlation with GA, CRL and FL, even when nothing is known about the ethnicity of the population.

A disease causing deletion of 29 base pairs in intron 15 in the MKS1 gene is highly associated with the campomelic variant of the Meckel-Gruber syndrome.

Meckel-Gruber syndrome (MKS) is an autosomal recessive disorder causing severe defects in the developing central nervous system and other organs. Recently, mutations in the MKS1 gene have been identified as disease causing in individuals of Finnish MKS families. The primary aim of the present study was to assess the frequency of the 'Finnish founder mutation' (29 bp IVS15-7_35) in the MKS1 gene in 20 aborted fetuses with a diagnosis of MKS. The secondary aim was to screen for novel mutations in the coding sequence of the MKS1 gene of MKS fetuses and to obtain genotype-phenotype correlations where possible. Furthermore, we evaluated the carrier rate of a deletion of 29 bp in intron 15 of the MKS1 gene in a German population. To identify and characterize mutations in the MKS1 gene, sequence analyses and quantitative real time polymerase chain reaction studies were performed. We could identify the same type of mutation, a deletion of 29 bp in intron 15 of the MKS1 gene, in 8 out of the 20 cases studied. Six out of the eight cases with such a mutation displayed the campomelic variant of MKS. The carrier frequency among 519 healthy German individuals was 1:260. This deletion in the MKS1 gene is highly associated with a distinct subtype of the MKS, namely the campomelic variant. In individuals of European origin suffering from the campomelic MKS variant, the described deletion is highly likely to be causative. Regarding the results of our study, the incidence of MKS in Germany can be estimated as 1:135,000. In families with a known mutation in the MKS1 gene, it is now possible to offer an early prenatal testing, for example with chorionic villus sampling and mutation analysis.