Search

Lissencephaly is a severe brain malformation in which failure of neuronal migration results in agyria or pachygyria and in which the brain surface appears unusually smooth. It is often associated with microcephaly, profound intellectual disability, epilepsy, and impaired motor abilities. Twenty-two genes are associated with lissencephaly, accounting for approximately 80% of disease. Here we report on 12 individuals with a unique form of lissencephaly; these individuals come from eight unrelated families and have bi-allelic mutations in APC2, encoding adenomatous polyposis coli protein 2. Brain imaging studies demonstrate extensive posterior predominant lissencephaly, similar to PAFAH1B1-associated lissencephaly, as well as co-occurrence of subcortical heterotopia posterior to the caudate nuclei, "ribbon-like" heterotopia in the posterior frontal region, and dysplastic in-folding of the mesial occipital cortex. The established role of APC2 in integrating the actin and microtubule cytoskeletons to mediate cellular morphological changes suggests shared function with other lissencephaly-encoded cytoskeletal proteins such as α-N-catenin (CTNNA2) and platelet-activating factor acetylhydrolase 1b regulatory subunit 1 (PAFAH1B1, also known as LIS1). Our findings identify APC2 as a radiographically distinguishable recessive form of lissencephaly.

Karyomegalic interstitial nephritis (KIN) is a rare entity associated with biallelic FAN1 (FANCD2/FANCI‐Associated Nuclease 1) gene variants. In FAN1‐related KIN, abnormal liver function tests and respiratory involvement are common, in addition to chronic kidney disease. Karyomegalic changes have also been reported in many other organs in patients with FAN1‐related KIN in various studies. We report the case of a 35‐year‐old male with chronic kidney disease of unknown aetiology, concurrent recurrent upper and lower respiratory tract infections, and elevated liver function test results with unidentified aetiology. The patient's family history was remarkable for consanguineous parent marriage and history of kidney transplantation in his aunt. A kidney biopsy was performed, which was consistent with KIN. Clinical exome sequencing revealed a homozygous nonsense variant NM_014967.5 (FAN1): c. 2260C > T (p.Arg754Ter). According to the American College of Medical Genetics (ACMG) criteria, this variant is pathogenic and, to the best of our knowledge, has not been previously reported, homozygously. Therefore, the histopathological and clinical diagnoses of KIN were confirmed by genetic studies in our patient. This case report expands the genetic spectrum of FAN1‐related KIN, and briefly reviews the current literature data. [ABSTRACT FROM AUTHOR]

Introduction: Counseling osteogenesis imperfecta (OI) pregnancies is challenging due to the wide range of onsets and clinical severities, from perinatal lethality to milder forms detected later in life. Methods: Thirty-eight individuals from 36 families were diagnosed with OI through prenatal ultrasonography and/or postmortem clinical and radiographic findings. Genetic analysis was conducted on 26 genes associated with OI in these subjects that emerged over the past 20 years; while some genes were examined progressively, all 26 genes were examined in the group where no pathogenic variations were detected. Results: Prenatal and postnatal observations both consistently showed short limbs in 97%, followed by bowing of the long bones in 89%. Among 32 evaluated cases, all exhibited cranial hypomineralization. Fractures were found in 29 (76%) cases, with multiple bones involved in 18 of them. Genetic associations were disclosed in 27 families with 22 (81%) autosomal dominant and five (19%) autosomal recessive forms, revealing 25 variants in six genes (COL1A1, COL1A2, CREB3L1, P3H1, FKBP10, and IFITM5), including nine novels. Postmortem radiological examination showed variability in intrafamily expression of CREBL3- and P3H1-related OI. Conclusion: Prenatal diagnosis for distinguishing OI and its subtypes relies on factors such as family history, timing, ultrasound, genetics, and postmortem evaluation. [ABSTRACT FROM AUTHOR]

We report on 314 fetal cases from 297 unrelated families with skeletal dysplasia evaluated in the postmortem period from 2000 to 2017 at a single clinical genetics center in İstanbul, Turkey. The definite diagnostic yield was 40% during the prenatal period, while it reached 74.5% when combined with postmortem clinical and radiological evaluation. Molecular analyses were performed in 25.5% (n: 76) of families, and 21 novel variants were identified. Classification according to International Skeletal Dysplasia Society‐2019 revision revealed limb hypoplasia‐reduction defects group (39) as the leading one, 24.5%, then followed by FGFR3 chondrodysplasias, osteogenesis imperfecta, and decreased mineralization and polydactyly‐syndactyly‐triphalangism groups 13.6, 11.1, and 8.9%, respectively. The inheritance pattern was autosomal recessive in 54% and autosomal dominant in 42.6% of index cases. The overall consanguinity rate of the cohort was 33%. The high prevalence of ultrarare diseases along with two or more unrelated autosomal recessive entities running in the same family was noteworthy. This study highlights the pivotal role of postmortem evaluation by an experienced clinical geneticist to achieve a high diagnostic yield in fetal skeletal dysplasia cohorts. The cohort is not only a representation of the spectrum of skeletal dysplasias in a population with a high consanguinity rate but also provides an ideal research group to work on to identify the unknowns of early fetal life. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to present and investigate fetal cases with hand anomalies by discussing their antenatal and postmortem findings. Materials and Methods: This retrospective review re-evaluates fetal cases identified antenatally with hand anomalies including polydactyly, syndactyly, reduction defects, and oligodactyly. The following data were collected from the patients’ medical records: Demographic information, family histories, X-ray images, photographs, and cytogenetic/molecular findings. The study also performed a chromosome analysis, array-comparative genomic hybridization (CGH), and Sanger sequencing of FGFR2 and GLI3 genes. Results: This study involved 18 cases with hand anomalies, all of which were diagnosed antenatally. Three cases were diagnosed with Greig cephalopolysyndactyly, Apert Syndrome, and triploidy, respectively. Conclusions: Fetal ultrasonography is the most valuable tool for providing prenatal diagnosis. Prenatal detection of hand anomalies causes great anxiety for parents; therefore, making an accurate diagnosis list is important for the prenatal period. Prenatal diagnosis and management of hand anomalies must involve a multidisciplinary team composed of a perinatologist, a clinical geneticist, and a hand surgeon. [ABSTRACT FROM AUTHOR]

This article discusses the case of a 42-year-old Caucasian woman who was diagnosed with a rare genetic disorder called transaldolase deficiency (TALDO-D). The patient presented with glycosuria, hypouricemia, mild kidney dysfunction, and a history of liver cirrhosis and atrial septal defect. The diagnosis was confirmed through genetic testing, which revealed a homozygous likely pathogenic variant in the TALDO1 gene. The patient was treated with N-acetylcysteine and sodium bicarbonate, and her liver and kidney function remained stable during the two-year follow-up. The article highlights the importance of considering TALDO-D in cases of multisystemic disorders with renal involvement. [Extracted from the article]