Characterization of three ciliopathy pedigrees expands the phenotype associated with biallelic C2CD3 variants

Whole exome sequencing (WES) is utilized in diagnostic odyssey cases to identify the underlying genetic cause associated with complex phenotypes. Recent publications suggest that WES reveals the genetic cause in ~25% of these cases and is most successful when applied to children with neurological disease. The residual 75% of cases remain genetically elusive until more information becomes available in the literature or functional studies are pursued. WES performed on three families with presumed ciliopathy diagnoses, including orofaciodigital (OFD) syndrome, fetal encephalocele, or Joubert-related disorder, identified compound heterozygous variants in C2CD3. Biallelic variants in C2CD3 have previously been associated with ciliopathies, including OFD syndrome type 14 (OFD14; MIM: 615948). As three of the six identified variants were predicted to affect splicing, exon-skipping analysis using either RNA sequencing or PCR-based methods were completed to determine the pathogenicity of these variants, and showed that each of the splicing variants led to a frameshifted protein product. Using these studies in combination with the 2015 ACMG guidelines, each of the six identified variants were classified as either pathogenic or likely pathogenic, and are therefore likely responsible for our patients' phenotypes. Each of the families had a distinct clinical phenotype and severity of disease, extending from lethal to viable. These findings highlight that there is a broad phenotypic spectrum associated with C2CD3-mediated disease and not all patients present with the typical features of OFD14.

[Prenatal diagnosis of central nervous system malformations]

The prenatal diagnosis of fetal malformations have been the subject of numerous publications in the literature. This has dramatically increased in the last 15 years, mainly due to the advent of high-resolution ultrasound. In addition adequate guidelines issued by professional organizations have encouraged the universal approach to the imaging of fetal anatomy as well as malformations. One of the most significant groups of the fetal anomalies is the central nervous system malformation. Due to its prevalence and severity the praenatal diagnostics of central nervous system malformations got basic significance. In this review we attempted to summarize the recent informations concerning the prenatal diagnostics of the central nervous system anomalies.

Intrapancreatic accessory spleen

A case of accessory spleen located in the tail of the pancreas in a stillbirth male foetus is reported. The congenital anomaly was revealed at autopsy. The intrapancreatic spleen was well demarcated and was composed of red and white pulp; however, same pancreatic ducts were intermingled with the splenic parenchyma. As well as the intrapancreatic lesion another minute accessory spleen was also found at the hilum of the proper organ. Since a lack of morphological features of trisomy 13 syndrome were found in the foetus, the ectopic spleens were regarded as incidental findings.

Holoprosencephaly and ectrodactyly: Report of three new patients and review of the literature

Holoprosencephaly (HPE) and ectrodactyly represent congenital malformations of the developing forebrain and developing digits, respectively. The combination of these conditions is rare, with only 15 cases known to date (12 previously reported, and 3 new cases described here). While the findings in these patients overlap with previously described genetic conditions, the similarity in phenotypes among these patients has led to the establishment of a at least one distinct syndrome: HPE, ectrodactyly, and bilateral cleft lip-palate syndrome (OMIM 300571). There has been great interest in identifying a genetic cause for the findings in patients with HPE and ectrodactyly; however the cause(s) of this rare association still remain unknown.

Is it always possible to determine a diagnosis? Prenatal ultrasonography, post mortem magnetic resonance, autopsy

Pathological-anatomical autopsy is the gold standard for determining of foetal abnormalities, but in some cases its role is limited (pathology of central nervous system, in particular, in case of ventricular dilatation or developed autolysis). In pathology of central nervous system, where insufficiency of autopsy can occur, additional post mortem magnetic resonance imaging (MRI) is performed to determine type of malformation. In this case report, we would like to point out the fact that although all investigating methods including post mortem magnetic resonance and autopsy (incl. imunohistochemical tests) are used, this need not necessarily result in a clear diagnostic conclusion of the aborted foetus. Post mortem MRI visualized pathology: dilatation of both lateral ventricals, more in the left and, above all, a pathological focus parasagittaly on the right with haemorrhage and cystic component; it raised a suspicion on ependymoma. However imunohistochemical test did not give an unambiguous conclusion; therefore diagnosis based on MRI could not be uniquely verified.

Association between exposure to emissions from the oil and gas industry and pathology of the immune, nervous, and respiratory systems, and skeletal and cardiac muscle in beef calves

To determine potential associations between emissions from oil and gas field facilities and the risk of lesions in the immune, nervous, and respiratory systems of beef calves, researchers examined tissue samples collected from 1,531 cases with exposure data, which included aborted fetuses, stillbirths, and calf mortalities from 203 cow-calf herds, by means of histopathology. The researchers prospectively measured exposure to sulfur dioxide, hydrogen sulfide, and volatile organic compounds by using air-monitoring data from passive monitors. They used the density of facilities surrounding each pasture as a second measure of exposure. Each tissue was classified by the presence or absence of a series of specified lesions, including those associated with degeneration, necrosis, infection, inflammation, anomaly, lympholysis (for lymphoid tissue), and proliferation (for the respiratory system). Exposure was not associated with the risk of lesions to tissues of either the immune or nervous system in calves that were aborted or died in spring 2002. Exposures to sulfur dioxide and hydrogen sulfide were not significantly associated with the risk of lesions to respiratory tissues in calves that were born alive in spring 2002. Increasing postnatal exposures to volatile organic compounds measured as benzene and toluene were associated with increased odds of respiratory lesions. The association between volatile organic compounds measured as benzene and respiratory lesions was significant for calves older than 3 weeks. During gestation, increasing exposure to sulfur dioxide was associated with increased odds of lesions in either the skeletal muscle or myocardium.

On the spectrum of limb-body wall complex, exstrophy of the cloaca, and urorectal septum malformation sequence

The limb-body wall complex (LBWC) is characterized by abdominal wall and limb defects, exstrophy of the cloaca (EC) by lack of closure of the lower abdominal wall and lack of cloacal septation, and the urorectal septum malformation sequence (URSMS) by absent perineal and anal openings, ambiguous genitalia, colonic, and renal anomalies. We report here on three fetuses whom have overlapping features of these disorders. Also we have reviewed the literature for cases with overlapping features of two or three of the above conditions. From the description of the cases reported on here and those in the literature, we propose that the overlap of features found among LBWC, EC, and URSMS represent a continuous spectrum of abnormalities, rather than three separate conditions. As such, we suggest that all three conditions may share a common etiology or pathogenetic mechanism.

Prenatal diagnosis of fetal exencephaly associated with amniotic band sequence at 17 weeks of gestation by fetal magnetic resonance imaging

We report a fetus with exencephaly diagnosed by fetal magnetic resonance imaging (MRI) at 17 weeks of gestation. Fetal ultrasound performed at 13 and 17 weeks of gestation suggested occipital encephalocele. However, the fetal MRI done at 17 weeks of gestation showed exencephaly and suggested amniotic bands as the cause. By providing early and precise information regarding the abnormality and the possible etiology, the fetal MRI enabled us to provide the couple and their families with accurate information regarding the low recurrence risk of this condition.

Giant omphalocele and “prune belly” sequence as components of the Beckwith-Wiedemann syndrome

We report a case of severe Beckwith-Wiedemann syndrome (BWS) in a fetus at 16 weeks of gestation. This presentation, incompatible with life, included a giant omphalocele and absence of abdominal wall musculature with extremely dilated bladder, as in the "prune belly" sequence. Adrenal cytomegaly pointed to BWS. Molecular analysis confirmed the diagnosis of BWS and showed an isolated demethylation of the KCNQ1OT1 gene. This report demonstrates that lethal fetal abdominal wall defects associated with adrenal cytomegaly are linked to epigenetic change of the 11p15 imprinted region.

Developmental toxicity studies of methyl ethyl ketoxime (MEKO) in rats and rabbits

The developmental toxicity of methyl ethyl ketoxime (MEKO), an industrial antioxidant used primarily as an antiskinning agent in alkyd paint, was investigated in rats and rabbits. Following preliminary dose range finding studies, groups of 25 pregnant rats or 18 pregnant rabbits were dosed by gavage with aqueous solutions of MEKO at 0, 60, 200, or 600 mg/kg (rats) or 0, 8, 14, 24, or 40 mg/kg (rabbits) on gestation days 6-15 or 6-18, respectively. In rats, dose-dependent clinical signs of maternal toxicity including reduced body weight gains were noted at 200 and 600 mg/kg. At 60 mg/kg and above enlarged spleens were observed at necropsy. The preliminary study found methemoglobin formation and reticulocytosis indicative of anemia at these dose levels. No treatment-related gestational effects, malformations or developmental variations were observed in the rats. In rabbits, 3 females aborted and 8 females were found dead at 40 mg/kg between gestation days 11 and 24. Clinical signs of maternal toxicity were present in surviving doses at this dose level. Body weight gains were reduced at 24 and 40 mg/kg. The preliminary study indicated maternal hematological effects in the rabbits similar to the rats at dose levels as low as 10 mg/kg. MEKO was not considered to have produced any treatment-related gestational effects, malformations or developmental variations in the rabbit at dose levels at or below 24 mg/kg. Because of excessive maternal mortality and abortions at the 40 mg/kg dose level, only 6 rabbits produced litters. The severe maternal toxicity and limited number of litters precluded a full assessment of developmental toxicity at 40 mg/kg. Nonetheless, MEKO did not appear to be teratogenic to the rabbit at this dose level.

Small inherited terminal duplication of 7q with hydrocephalus, cleft palate, joint contractures, and severe hypotonia

We report a 14-month-old girl with submucous cleft palate, resolving mild hydrocephalus, severe hypotonia and joint contractures. The finding of extreme hydrocephalus, cleft palate and club feet in a fetus of the mother's previous pregnancy suggested an inherited defect. Chromosome analysis and FISH studies in the proband revealed an abnormal homolog 13 resulting in a duplication of distal chromosome 7q, 7q35-qter, and a very small associated deletion of distal chromosome 13q, 13q34-qter. The mother showed the balanced translocation. Similar clinical signs have been described with larger distal 7q duplications. Our findings suggest that 7q35-qter, and possibly the gene for sonic hedgehog (SHH) on 7q36, is the critical region for the typical facial features and the profound hypotonia observed in the 'trisomy of distal 7q' syndrome.

A fetus suggesting an extension of theXK-aprosencephaly spectrum phenotype

We report a fetus with atelencephaly, bilateral radial aplasia/hypoplasia, ventriculoseptal defect and megacolon, this combination of anomalies being consistent with the diagnosis of XK-aprosencephaly syndrome. The facial dysmorphology of this fetus differs from that previously reported and together with reports on overlapping phenotypes suggests an extension of the XK-aprosencephaly spectrum.

Dysplastic cortical hyperostosis (Kozlowski-Tsuruta syndrome): report of a second case

We report a fetus from a pregnancy that was terminated at 26 weeks gestation for hydrops and short limb skeletal dysplasia. The parents were first cousins. Post mortem examination showed pulmonary hypoplasia and hepatomegaly. The radiographs showed shortening and cortical thickening of all long bones. The cortical thickening was most marked in the long bones, ribs, clavicles and scapulae but spared the skull vault, facial bones and pelvis. There were coronal clefts in the lower lumbar vertebrae. The clinical and radiological features of this fetus conform to those reported in a stillborn male by Kozlowski and Tsuruta in 1989 (Br J Radiol 62:376-378). This is the second reported case of this condition and confirms that it is a distinct and recognisable, lethal skeletal dysplasia. The parental consanguinity in our patient suggests that this condition may be inherited in an autosomal recessive manner.