Long-read transcriptome sequencing reveals allele-specific variants at high resolution.

Disturbance in the regulation of transcript structure plays a crucial role in human disease. In a recent study, Glinos et al. characterized allele-specific transcript alterations in long-read RNA sequencing (RNA-seq) data derived from multiple human tissues and provide a high-resolution view of how disease-associated genetic variants affect transcript structure.

Detection and evaluation of parameters influencing the identification of heterozygous-enriched regions in Holstein cattle based on SNP chip or whole-genome sequence data.

BACKGROUND: A heterozygous-enriched region (HER) is a genomic region with high variability generated by factors such as balancing selection, introgression, and admixture processes. In this study, we evaluated the genomic background of HERs and the impact of different parameters (i.e., minimum number of SNPs in a HER, maximum distance between two consecutive SNPs, minimum length of a HER, maximum number of homozygous allowed in a HER) and scenarios [i.e., different SNP panel densities and whole-genome sequence (WGS)] on the detection of HERs. We also compared HERs characterized in Holstein cattle with those identified in Angus, Jersey, and Norwegian Red cattle using WGS data. RESULTS: The parameters used for the identification of HERs significantly impact their detection. The maximum distance between two consecutive SNPs did not impact HERs detection as the same average of HERs (269.31 ± 787.00) was observed across scenarios. However, the minimum number of markers, maximum homozygous markers allowed inside a HER, and the minimum length size impacted HERs detection. For the minimum length size, the 10 Kb scenario showed the highest average number of HERs (1,364.69 ± 1,483.64). The number of HERs decreased as the minimum number of markers increased (621.31 ± 1,271.83 to 6.08 ± 21.94), and an opposite pattern was observed for the maximum homozygous markers allowed inside a HER (54.47 ± 195.51 to 494.89 ± 1,169.35). Forty-five HER islands located in 23 chromosomes with high Tajima's D values and differential among the observed and estimated heterozygosity were detected in all evaluated scenarios, indicating their ability to potentially detect regions under balancing selection. In total, 3,440 markers and 28 genes previously related to fertility (e.g., TP63, ZSCAN23, NEK5, ARHGAP44), immunity (e.g., TP63, IGC, ARHGAP44), residual feed intake (e.g., MAYO9A), stress sensitivity (e.g., SERPINA6), and milk fat percentage (e.g., NOL4) were identified. When comparing HER islands among breeds, there were substantial overlaps between Holstein with Angus (95.3%), Jersey (94.3%), and Norwegian Red cattle (97.1%), indicating conserved HER across taurine breeds. CONCLUSIONS: The detection of HERs varied according to the parameters used, but some HERs were consistently identified across all scenarios. Heterozygous genotypes observed across generations and breeds appear to be conserved in HERs. The results presented could serve as a guide for defining HERs detection parameters and further investigating their biological roles in future studies.

Novel Compound Heterozygous Variants in the FAS Gene Lead to Fetal Onset of Autoimmune Lymphoproliferative Syndrome (ALPS).

OBJECTIVE: FAS gene defects lead to autoimmune lymphoproliferative syndrome (ALPS), which is often inherited in an autosomal dominant and rarely in an autosomal recessive manner. We report a case of a newborn girl with novel compound heterozygous variants in FAS and reveal the underlying mechanism. METHODS: Whole-exome sequencing (WES) was used to identify pathogenic variants. Multiparametric flow cytometry analysis, phosflow analysis, and FAS-induced apoptosis assays were used to explore the effects of the variants on FAS expression, apoptosis, and immunophenotype. The HEK293T cells were used to assess the impact of the variants on protein expression and FAS-induced apoptosis. RESULTS: The patient was born with hepatosplenomegaly, anemia, and thrombocytopenia. She also experienced COVID-19, rotavirus infection, herpes simplex virus infection, and severe pneumonia. The proportion of double-negative T cells (DNTs) was significantly elevated. Novel FAS compound heterozygous variants c.310T > A (p.C104S) and c.702_704del (p.T235del) were identified. The apoptotic ability of T cells was defective, and FAS expression on the surface of T cells was deficient. The T235del variant decreased FAS expression, and the C104S protein remained in the endoplasmic reticulum (ER) and could not translocate to the cell surface. Both mutations resulted in loss-of-function in terms of FAS-induced apoptosis in HEK293T cells. The DNTs were mainly terminally differentiated T (TEMRA) and CD45RA+HLA-DR+, with high expression of CD85j, PD-1, and CD57. The percentage of Th1, Tfh, and autoreactive B cells were significantly increased in the patient. The abnormal immunophenotyping was partially attenuated by sirolimus treatment. CONCLUSIONS: We identified two variants that significantly affect FAS expression or localization, leading to early disease onset of in the fetus. Abnormalities in the mTOR pathway are associated with a favorable response to sirolimus.

In silico analysis of the wild-type and mutant-type of BRCA2 gene.

BACKGROUND: The aim of this study was to conduct an in silico analysis of a novel compound heterozygous variant in breast cancer susceptibility gene 2 (BRCA2) to clarify its structure-function relationship and elucidate the molecular mechanisms underlying triple-negative breast cancer (TNBC). METHODS: A tumor biopsy sample was obtained from a 42-year-old Chinese woman during surgery, and a maxBRCA™ test was conducted using the patient's whole blood. We obtained an experimentally determined 3D structure (1mje.pdb) of the BRCA2 protein from the Protein Data Bank (PDB) as a relatively reliable reference. Subsequently, the wild-type and mutant structures were predicted using SWISS-MODEL and AlphaFold, and the accuracy of these predictions was assessed through the SAVES online server. Furthermore, we utilized a high ambiguity-driven protein-protein docking (HADDOCK) algorithm and protein-ligand interaction profiler (PLIP) to predict the pathogenicity of the mutations and elucidate pathogenic mechanisms that potentially underlies TNBC. RESULTS: Histological examination revealed that the tumor biopsy sample exhibited classical pathological characteristics of TNBC. Furthermore, the maxBRCA™ test revealed two compound heterozygous BRCA2 gene mutations (c.7670 C > T.pA2557V and c.8356G > A.pA2786T). Through performing in silico structural analyses and constructing of 3D models of the mutants, we established that the mutant amino acids valine and threonine were located in the helical domain and oligonucleotide binding 1 (OB1), regions that interact with DSS1. CONCLUSION: Our analysis revealed that substituting valine and threonine in the helical domain region alters the structure and function of BRCA2 proteins. This mutation potentially affects the binding of proteins and DNA fragments and disrupts interactions between the helical domain region and OB1 with DSS1, potentially leading to the development of TNBC. Our findings suggest that the identified compound heterozygous mutation contributes to the clinical presentation of TNBC, providing new insights into the pathogenesis of TNBC and the influence of compound heterozygous mutations in BRCA2.

A novel compound heterozygous variant of MYO7A in Usher syndrome type 1.

Usher syndrome (USH) is a recessive genetic disorder manifested by congenital sensorineural hearing loss and progressive retinitis pigmentosa, which leads to audiovisual impairment. We report a patient with Usher syndrome type 1 with new compound heterozygous MYO7A variants. A total of four members from the USH family were included. Medical history and retinal examinations were taken and genomic DNA from peripheral blood was extracted in the proband and other members. 381 retinal disease-associated genes were screened using targeted sequence capture array technology and Sanger sequencing was used to confirm the screening results. Scanning laser ophthalmoscope showed bone spicule pigmentary deposits in the mid-peripheral retina and whitish and thin retinal blood vessels especially in the arterioles. Optical coherence tomography showed that the centrality of the macular ellipsoid band disappeared in both eyes, and only remained near the fovea. Visual field examination showed a progressive loss of the visual field in a concentric pattern in both eyes. The electroretinography showed a significant decrease in the amplitudes of a- and b-waves in the scotopic and photopic condition. DNA sequencing identified the compound heterozygous variants including c.1003+1G > A: p. (?) and c.5957_5958del: p.G1987Lfs*50 of MYO7A, with the latter being novel. In this study, we found a novel compound heterozygous variant in MYO7A, which enriched the mutation spectrum and expanded our understanding of the heterogeneity of phenotype and genotype of Usher syndrome type 1.

New insights into the landscape of ALPL gene variants in patients with hypophosphatasia from the Global HPP Registry.

Hypophosphatasia (HPP) is a rare, inherited metabolic disease characterized by low tissue-nonspecific alkaline phosphatase activity due to ALPL gene variants. We describe ALPL variants from the observational, prospective, multinational Global HPP Registry. Inclusion in the analysis required a diagnosis of HPP, low serum ALP activity, and ≥1 ALPL variant. Of 1176 patients enrolled as of September 2022, 814 met inclusion criteria in Europe (48.9%), North America (36.7%), Japan (10.2%), Australia (2.6%), and elsewhere (1.6%). Most patients (74.7%) had 1 ALPL variant; 25.3% had ≥2 variants. Nearly all patients (95.6%) had known disease-causing variants; 4.4% had variants of uncertain significance. Disease-causing variants were predominantly missense (770/1556 alleles). The most common variants were c.571G>A (102/1628 alleles), c.1250A>G (66/1628 alleles), and c.1559del (61/1628 alleles). Variant profiles were generally consistent, except in Japan, where a higher proportion of patients (68.7%) had ≥2 ALPL variants, likely because more had disease onset before age 6 months (53.0% vs. 10.1%-23.1% elsewhere). Frameshift mutations (61/164 alleles) and inframe deletions (7/164 alleles) were more common in Japan. Twenty-three novel variants were discovered, each in a single geographic region, predominantly Europe. Analyses confirmed previously known ALPL variants, identified novel variants, and characterized geographic variation in frequency and type of ALPL variants in a large population.

A unique case of hyperammonemia due to CA5A deficiency: Impact of coexisting gene mutations, pseudogene, and microdeletion.

Carbonic anhydrase 5A (CA5A) belongs to a family of carbonic anhydrases which are zinc metalloenzymes involved in the reversible hydration of CO2 to bicarbonate. Mutations in CA5A are very rare and known to cause Carbonic anhydrase 5A deficiency (CA5AD), an autosomal recessive inborn error of metabolism characterized clinically by acute onset of encephalopathy in infancy or early childhood. CA5A also has two very identical pseudogenes whose interference may result in compromised accuracy in targeted sequencing. We report a unique case of CA5AD caused by compound heterozygous variant (NM_001739.2: c.721G>A: p.Glu241Lys & NM_001739.2: c.619-3420_c.774 + 502del4078bp) in an infant in order to expand the phenotypic spectrum and underscore the impact of pseudogenes, which can introduce complexities in molecular genetic analysis.

KIF11 Variants Associated With Novel Renal System Involvement-Two Cases That Expand the Phenotypic Spectrum of Microcephaly With or Without Chorioretinopathy, Lymphedema, or Impaired Intellectual Development.

Pathogenic variants in KIF11 are linked to microcephaly with or without chorioretinopathy, lymphedema, or impaired intellectual development (MCLMR). To our knowledge, renal phenotypes have not been described in the literature in association with KIF11-related disorders. This study is a case report of two probands with heterozygous pathogenic variants in KIF11 who presented with the common clinical features of MCLMR but also had additional renal involvement not previously reported as associated phenotypes of MCLMR, elucidating phenotypic expansion of this syndrome.

Expanding the phenotype of Harel-Yoon syndrome: A case report suggesting a genotype/phenotype correlation.

Harel-Yoon syndrome (HAYOS) is a unique neurodevelopmental genetic disorder characterized by hypotonia, spasticity, intellectual disability, hypertrophic cardiomyopathy, and global developmental delay. It primarily results from mutations in the ATAD3A gene, pivotal for mitochondrial function. This report presents a 5-year-old girl with HAYOS harboring a de novo heterozygous variant c.1064G>A; (p.G355D) in ATAD3A. Her clinical profile includes delayed milestones, hypotonia, spastic quadriplegia, and ptosis. Notably, dermatologic anomalies such as hypopigmentation, café au lait macules, and freckling are observed, expanding the known phenotype of HAYOS. The inclusion of dermatologic features challenges our understanding of the syndrome and emphasizes the importance of further research to elucidate the molecular connections between ATAD3A mutations and dermatologic manifestations.

Genetic characterization of KCNQ1 variants improves risk stratification in type 1 long QT syndrome patients.

AIMS: KCNQ1 mutations cause QTc prolongation increasing life-threatening arrhythmias risks. Heterozygous mutations [type 1 long QT syndrome (LQT1)] are common. Homozygous KCNQ1 mutations cause type 1 Jervell and Lange-Nielsen syndrome (JLNS) with deafness and higher sudden cardiac death risk. KCNQ1 variants causing JLNS or LQT1 might have distinct phenotypic expressions in heterozygous patients. The aim of this study is to evaluate QTc duration and incidence of long QT syndrome-related cardiac events according to genetic presentation. METHODS AND RESULTS: We enrolled LQT1 or JLNS patients with class IV/V KCNQ1 variants from our inherited arrhythmia clinic (September 1993 to January 2023). Medical history, ECG, and follow-up were collected. Additionally, we conducted a thorough literature review for JLNS variants. Survival curves were compared between groups, and multivariate Cox regression models identified genetic and clinical risk factors. Among the 789 KCNQ1 variant carriers, 3 groups were identified: 30 JLNS, 161 heterozygous carriers of JLNS variants (HTZ-JLNS), and 550 LQT1 heterozygous carriers of non-JLNS variants (HTZ-Non-JLNS). At diagnosis, mean age was 3.4 ± 4.7 years for JLNS, 26.7 ± 21 years for HTZ-JLNS, and 26 ± 21 years for HTZ-non-JLNS; 55.3% were female; and the mean QTc was 551 ± 54 ms for JLNS, 441 ± 32 ms for HTZ-JLNS, and 467 ± 36 ms for HTZ-Non-JLNS. Patients with heterozygous JLNS mutations (HTZ-JLNS) represented 22% of heterozygous KCNQ1 variant carriers and had a lower risk of cardiac events than heterozygous non-JLNS variant carriers (HTZ-Non-JLNS) [hazard ratio (HR) = 0.34 (0.22-0.54); P < 0.01]. After multivariate analysis, four genetic parameters were independently associated with events: haploinsufficiency [HR = 0.60 (0.37-0.97); P = 0.04], pore localization [HR = 1.61 (1.14-1.2.26); P < 0.01], C-terminal localization [HR = 0.67 (0.46-0.98); P = 0.04], and group [HR = 0.43 (0.27-0.69); P < 0.01]. CONCLUSION: Heterozygous carriers of JLNS variants have a lower risk of cardiac arrhythmic events than other LQT1 patients.

Novel compound heterozygous mutations of the NPC1 gene associated with Niemann-pick disease type C: a case report and review of the literature.

BACKGROUND: Niemann-Pick Disease type C is a fatal autosomal recessive lipid storage disorder caused by NPC1 or NPC2 gene mutations and characterized by progressive, disabling neurological deterioration and hepatosplenomegaly. Herein, we identified a novel compound heterozygous mutations of the NPC1 gene in a Chinese pedigree. CASE PRESENTATION: This paper describes an 11-year-old boy with aggravated walking instability and slurring of speech who presented as Niemann-Pick Disease type C. He had the maternally inherited c.3452 C > T (p. Ala1151Val) mutation and the paternally inherited c.3557G > A (p. Arg1186His) mutation using next-generation sequencing. The c.3452 C > T (p. Ala1151Val) mutation has not previously been reported. CONCLUSIONS: This study predicted that the c.3452 C > T (p. Ala1151Val) mutation is pathogenic. This data enriches the NPC1 gene variation spectrum and provides a basis for familial genetic counseling and prenatal diagnosis.

Analytical validation of the amplification refractory mutation system polymerase chain reaction-capillary electrophoresis assay to diagnose spinal muscular atrophy.

OBJECTIVES: Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by homozygous deletion and compound heterozygous mutations in survival motor neuron 1 (SMN1), with severity tied to the copy number of survival motor neuron 2 (SMN2). This study aimed to develop a rapid and comprehensive method for the diagnosis of SMA. METHODS: A total of 292 children with clinically suspected SMA and 394 family members were detected by the amplification refractory mutation system polymerase chain reaction-capillary electrophoresis (ARMS-PCR-CE) method, which targeted 19 reported mutations, and the results were compared with those in multiplex ligation-dependent probe amplification (MLPA). Individuals with identified point mutations were further confirmed by SMN1 long-range PCR and Sanger sequencing. RESULTS: A total of 202 children with SMA, 272 carriers, and 212 normal individuals were identified in this study. No difference was found in the R-value distribution of exons 7 and 8 in SMN1 and SMN2 among these cohorts, with coefficients of variation consistently below 0.08. To detect exon 7 and 8 copy numbers in SMN1 and SMN2, the ARMS-PCR-CE results were concordant with those of MLPA. Approximately 4.95 % (10/202) of the study patients had compound heterozygous mutations. CONCLUSIONS: The ARMS-PCR-CE assay is a comprehensive, rapid, and accurate diagnostic method for SMA that simultaneously detects copy numbers of exons 7 and 8 in SMN1/SMN2, as well as 19 point mutations in SMN1 and 2 enhancers in SMN2. This approach can effectively reduce the time frame for diagnosis, facilitating early intervention and preventing birth defects.

Two cases of venous thromboembolism in siblings after splenectomy due to a novel PROC gene mutation.

BACKGROUND: Venous thromboembolism(VTE)is a common multifactorial disease. Anticoagulant protein deficiency is the most usual hereditary thrombophilia in the Chinese people, which includes protein C(PC), protein S and antithrombin deficiencies. CASE PRESENTATION: A retrospective analysis was conducted on clinical manifestations, laboratory tests, genetic information, and other relevant data of siblings diagnosed with VTE in 2020 at the Department of Pediatrics of Shenzhen Second People's Hospital. The proband, a 12-year-old female, was admitted to the hospital in December 2020 with a complaint of pain in the left lower limb for four days. The examination found that the PC activity was 53%, and B-ultrasound showed bilateral thrombosis of the great saphenous vein in the thigh segment. The proband's younger brother, a 10-year-old male, was admitted to the hospital in January 2021 due to right lower limb pain for two weeks. PC activity is 40%. B-ultrasound showed superficial venous thrombosis in the left lower limb and upper limb. Both siblings suffered from thalassemia and underwent splenectomy before recurrent thrombosis occurred. The proband's mother was asymptomatic, and her PC activity was 45%. Both cases were treated with warfarin anticoagulation, and their symptoms improved. The proband's mother was found to have a heterozygous mutation at this locus through Sanger sequencing. CONCLUSION: Protein C deficiency should be considered for venous thromboembolism in childhood. The heterozygous mutation 1204 A > G in PROC exon 9 in this family is reported for the first time.

A compound heterozygous mutation of ERCC8 is responsible for a family with Cockayne syndrome.

BACKGROUND: Cockayne syndrome is an inherited heterogeneous defect in transcription-coupled DNA repair (TCR) cause severe clinical syndromes, which may affect the nervous system development of infants and even lead to premature death in some cases. ERCC8 diverse critical roles in the nucleotide excision repair (NER) complex, which is one of the disease-causing genes of Cockayne syndrome. METHODS AND RESULTS: The mutation of ERCC8 in the patient was identified and validated using WES and Sanger sequencing. Specifically, a compound heterozygous mutation (c.454_460dupGTCTCCA p. T154Sfs*13 and c.755_759delGTTTT p.C252Yfs*3) of ERCC8 (CSA) was found, which could potentially be the genetic cause of Cockayne syndrome in the proband. CONCLUSION: In this study, we identified a novel heterozygous mutation of ERCC8 in a Chinese family with Cockayne syndrome, which enlarging the genetic spectrum of the disease.

Heterozygous RB1 mutation enhanced ATP production in human iPSC-derived retinal organoids.

BACKGROUND: Recent in vitro studies using RB1+/- fibroblasts and MSCs have shown molecular and functional disruptions without the need for biallelic loss of RB1. However, this was not reflected in the recent in vitro studies employing RB1+/- retinal organoids. To gain further insights into the molecular disruptions in the RB1+/- retinal organoids, we performed a high throughput RNA sequencing analysis. METHODS AND RESULTS: iPSCs were generated from RB1+/+ and RB1+/- OAMSCs derived from retinoblastoma patients. RB1+/+ and RB1+/- iPSCs were subjected to a step-wise retinal differentiation protocol. Retinal differentiation was evaluated by Real-time PCR and flow cytometry analysis of the retinal markers. To gain further insights into the molecular differences in RB1+/- retinal organoids, a high throughput RNA sequencing followed by differential gene expression analysis and gene set enrichment analysis (GSEA) was performed. The analysis revealed a shift from the regular metabolic process of glycolysis to oxidative phosphorylation in the RB1+/- retinal organoids. To investigate further, we performed assays to determine the levels of pyruvate, lactate and ATP in the retinal organoids. The results revealed significant increase in ATP and pyruvate levels in RB1+/- retinal organoids of day 120 compared to that of the RB1+/+. The results thus revealed enhanced ATP production in the RB1+/- retinal organoids. CONCLUSION: The study provides novel insights into the metabolic phenotype of heterozygous RB1 mutant suggesting dysregulation of energy metabolism and glycolytic pathways to be first step even before the changes in cellular proliferation or other phenotypic consequences ensue.

Decreased water exchange rate across blood-brain barrier in hereditary cerebral small vessel disease.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and heterozygous HTRA1 mutation-related cerebral small vessel disease (CSVD) are the two types of dominant hereditary CSVD. Blood-brain barrier (BBB) failure has been hypothesized in the pathophysiology of CSVD. However, it is unclear whether there is BBB damage in the two types of hereditary CSVD, especially in heterozygous HTRA1 mutation-related CSVD. In this study, a case-control design was used with two disease groups including CADASIL (n = 24), heterozygous HTRA1 mutation-related CSVD (n = 9) and healthy controls (n = 24). All participants underwent clinical cognitive assessments and brain MRI. Diffusion-prepared pseudo-continuous arterial spin labelling was used to estimate the water exchange rate across the BBB (kw). Correlation and multiple linear regression analyses were used to examine the association between kw and disease burden and neuropsychological performance, respectively. Compared with the healthy controls, kw in the whole brain and multiple brain regions was decreased in both CADASIL and heterozygous HTRA1 mutation-related CSVD patients (Bonferroni-corrected P < 0.007). In the CADASIL group, decreased kw in the whole brain (ß = -0.634, P = 0.001), normal-appearing white matter (ß = -0.599, P = 0.002) and temporal lobe (ß = -0.654, P = 0.001) was significantly associated with higher CSVD score after adjusting for age and sex. Reduced kw in the whole brain was significantly associated with poorer neuropsychological performance after adjusting for age, sex and education in both CADASIL and heterozygous HTRA1 mutation-related CSVD groups (ß = 0.458, P = 0.001; ß = 0.884, P = 0.008). This study showed that there was decreased water exchange rate across the BBB in both CADASIL and heterozygous HTRA1 mutation-related CSVD patients, suggesting a common pathophysiological mechanism underlying the two types of hereditary CSVD. These results highlight the potential use of kw for monitoring the course of CADASIL and heterozygous HTRA1 mutation-related CSVD, a possibility which should be tested in future research.

Review of patients with achondroplasia: a single-center's experience with follow-up and associated morbidities.

Achondroplasia (ACH; MIM #100,800), caused by a heterozygous gain of function pathogenic variant in the fibroblast growth factor receptor 3 gene (FGFR3; MIM*134,934), is the most prevalent and most readily identifiable cause of disproportionate short stature that is compatible with life. In addition, individuals with achondroplasia face significant medical, functional, and psychosocial challenges throughout their lives. This study assessed associated morbidities in patients with achondroplasia at a single center in Turkey. In this study, the clinical findings and associated morbidities of a group of patients with achondroplasia (n = 68) with clinical multidisciplinary follow-up at a single center between the years 2005-2023 are evaluated retrospectively. A total of 68 patients, 30 male (44.1%) and 38 female (55.9%), were evaluated. In the majority (84.2%) of patients, shortness of extremities was detected in the prenatal period at an average of 28.7 gestational weeks (± 3.6 SDS) with the aid of ultrasonography. More than half (n = 34/63, 54%) of the patients had a father of advanced paternal age (≥ 35 years). Among the complications, respiratory system manifestations, including obstructive sleep apnea (70%), ear-nose-throat manifestations including adenoid hypertrophy (56.6%) and otitis media (54.7%), neurological manifestations due to foramen magnum stenosis (53.2%), and skeletal manifestations including scoliosis (28.8%), are represented among the most common. The mortality rate was 7.3% (n = 5/68).Conclusion: This study not only represents the first retrospective analysis of the associated morbidities of patients with achondroplasia from a single center in Turkey but also will provide a reference point for future studies.

Prenatal Diagnosis of a KIDINS220 De Novo Heterozygous Variant in a Fetus With a Complex CNS Anomaly.

Following termination of pregnancy due to multiple brain malformations, a non-consanguineous couple of Jewish descent sought genetic counseling. Brain malformations identified on neurosonogram included corpus callosum dysgenesis, abnormal brain stem morphology, abnormal cortical sulcation and hypertelorism. Trio exome sequencing revealed a heterozygous de novo likely pathogenic variant in KIDINS220 gene. Heterozygous variants in KIDINS220 have been linked to spastic paraplegia, intellectual disability, nystagmus, and obesity syndrome (SINO). Reports on prenatal findings are limited and primarily consist of cases of ventriculomegaly. We describe a more severe clinical presentation in a case with a heterozygous variant.

A novel compound heterozygous PCDH15 variants is associated with arRP in a Chinese pedigree.

BACKGROUND: Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal diseases. However, it is still not well understand about the relationship between PCDH15 variants and RP. METHODS: In this study, we enrolled a Chinese autosomal recessive retinitis pigmentosa (arRP) pedigree and identified the causative gene in the proband by targeted whole exome sequencing (WES). The variants were validated in the family members by Sanger sequencing and co-segregation analysis. RESULTS: Novel compound heterozygous, Frame shift variants of the PCDH15 gene, NM_001384140.1:c.4368 - 2147_4368-2131del and NM_001384140.1:c exon19:c.2505del: p. T836Lfs*6 were identified in the arRP pedigree, which co-segregated with the clinical RP phenotypes. The PCDH15 protein is highly conserved among species. CONCLUSION: This is the first study to identify novel compound heterozygous variants c.4368 - 2147_4368-2131del and c.2505del(p.T836Lfs*6) in the PCDH15 gene which might be disease-causing variants, and extending the variant spectra. All above findings may be contribute to genetic counseling, molecular diagnosis and clinical management of arRP disease.

Controversy between biopsy and risk in children with proteinuria: is there a paradigm war?

BACKGROUND: Proteinuria is a prevalent symptom of pediatric nephrology, while kidney biopsy remains the gold standard for kidney tissue analysis, and it is currently controversial. We report the rare case that the mutation in the AMN gene was considered to cause chronically isolated proteinuria and also suggest that renal biopsy should be chosen with caution in children with chronic isolated non-nephrotic levels of proteinuria and that genetic testing may be feasible for the early precise diagnosis. CASE PRESENTATION: A 35-month-old boy presented with excessive urine foaming for more than half a month; his proteinuria was considered non-nephrotic range and urine protein electrophoresis was suggestive of mixed proteinuria; other than that, the investigations are non-specific. Given the child's chronic isolated proteinuria and good renal function, we chose to refine the genetic test rather than a renal biopsy; a compound heterozygous variant was found in the AMN gene of this child which was caused by a point mutation in the father, and a partial chromosomal deletion in the mother. CONCLUSIONS: Cubilin(encoded by CUBN), amnionless(encoded by AMN), and megalin form a multiligand receptor complex; CUBN or AMN gene variants have been implicated as a hereditary cause of megaloblastic anemia, proteinuria, and neurological impairment. In the past few decades, chronic isolated proteinuria caused by CUBN gene variants is benign, non-progressive, and has normal renal function. However, the child is the first reported case of isolated proteinuria of AMN gene mutation, indicating that the earlier diagnostic genetic sequencing in an otherwise well, not nephrotic proteinuria child may be a convenient, cost-effective, and harmless option, challenging the traditional paradigm.