Cystic phenotype and chronic kidney disease in autosomal dominant Alport syndrome.

BACKGROUND AND HYPOTHESIS: Autosomal Dominant Alport Syndrome (ADAS), also known as Thin Basement Membrane Disease (TBMD), is caused by pathogenic variants in COL4A3 and COL4A4 genes. A cystic phenotype has been described in some patients with TBMD, but no genetic studies were performed. We conducted a genetic and radiologic investigation in a cohort of ADAS patients to analyze the prevalence of multicystic kidney disease (MKD) and its association with Chronic Kidney Disease (CKD). METHODS: Retrospective single-center cohort study. Thirty-one patients showing pathogenic or likely pathogenic variants in COL4A3 or COL4A4 from a cohort of 79 patients with persistent microscopic hematuria were included. Mean follow-up was 9.4±9.6 years. The primary objective of the study was to determine the prevalence of MKD in the cohort of ADAS patients. Secondary objectives were to determine risk factors associated with an eGFR<45 ml/min/1.73m2 at the time of genetic and radiologic evaluation and to investigate the coexistence of other genetic abnormalities associated with familial hematuria and cystic kidney disease. RESULTS: MKD was found in 16 patients (52%). Mean number of cysts per kidney was 12.7±5.5. No genetic abnormalities were found in a panel of 101 other genes related to familial hematuria, focal segmental glomerulosclerosis and cystic kidney disease. A greater number of patients with MKD had an eGFR<45 ml/min/1.73m2 (63% vs 7%, p=0.006) and more advanced CKD than patients without MKD. The annual rate of eGFR decline was greater in patients with MKD: -1.8 vs 0.06 ml/min/1.73m2/year (p=0.009). By multivariable linear regression analysis, the main determinants of eGFR change per year were time-averaged proteinuria (p=0.002) and MKD (p=0.02). CONCLUSION: MKD is commonly found in ADAS and is associated with a worse kidney outcome. No pathogenic variants were found in genes other than COL4A3/COL4A4.

Expanding the Phenotypic Spectrum of Alazami Syndrome: Two Unrelated Spanish Families.

Alazami syndrome is a rare disorder with an autosomal recessive inheritance caused by pathogenic biallelic variants in the LARP7 gene. Clinically, it is mainly characterized by short stature, intellectual disability, and dysmorphic facial features. However, the phenotype is not yet well-defined because less than 50 cases have been described to date. Here, we report three new patients from two unrelated Spanish families who, in addition to the defined features of Alazami syndrome, also exhibit unique features that broaden the phenotypic spectrum of the syndrome. Moreover, we describe the novel frameshift variant c.690_699delins27 in the LARP7 gene, in which loss of function is a known mechanism of Alazami syndrome.

Heterozygous and Homozygous Variants in SORL1 Gene in Alzheimer's Disease Patients: Clinical, Neuroimaging and Neuropathological Findings.

In the last few years, the SORL1 gene has been strongly implicated in the development of Alzheimer's disease (AD). We performed whole-exome sequencing on 37 patients with early-onset dementia or family history suggestive of autosomal dominant dementia. Data analysis was based on a custom panel that included 46 genes related to AD and dementia. SORL1 variants were present in a high proportion of patients with candidate variants (15%, 3/20). We expand the clinical manifestations associated with the SORL1 gene by reporting detailed clinical and neuroimaging findings of six unrelated patients with AD and SORL1 mutations. We also present for the first time a patient with the homozygous truncating variant c.364C>T (p.R122*) in SORL1, who also had severe cerebral amyloid angiopathy. Furthermore, we report neuropathological findings and immunochemistry assays from one patient with the splicing variant c.4519+5G>A in the SORL1 gene, in which AD was confirmed by neuropathological examination. Our results highlight the heterogeneity of clinical presentation and familial dementia background of SORL1-associated AD and suggest that SORL1 might be contributing to AD development as a risk factor gene rather than as a major autosomal dominant gene.

First female with Allan-Herndon-Dudley syndrome and partial deletion of X-inactivation center.

Allan-Herndon-Dudley is an X-linked recessive syndrome caused by pathogenic variants in the SLC16A2 gene. Clinical manifestations are a consequence of impaired thyroid metabolism and aberrant transport of thyroid hormones to the brain. Carrier females are generally asymptomatic and may show subtle symptoms of the disease. We describe a female with a complete Allan-Herndon-Dudley phenotype, carrying a de novo 543-kb deletion of the X chromosome. The deletion encompasses exon 1 of the SLC16A2 gene and JPX and FTX genes; it is known that the latter two genes participate in the X-inactivation process upregulating XIST gene expression. Subsequent studies in the patient demonstrated the preferential expression of the X chromosome with the JPX and FTX deletion.

First patient with mosaic NOTCH3 gene pathogenic variant. Unrevealed mosaicisms and importance of their detection.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small vessel disease caused predominantly by pathogenic variants in NOTCH3 gene. Neither germline nor somatic mosaicism has been previously published in NOTCH3 gene. CADASIL is inherited in an autosomal dominant manner; only rare cases have been associated with de novo pathogenic variants. Mosaicism is more common than previously thought because mosaic variants often stay unrevealed. An apparently de novo variant might actually be a consequence of a parental mosaicism undetectable with Sanger sequencing, especially in the case of low grade mosaicism. Parental testing by sensitive tools like deep targeted next-generation sequencing (NGS) analysis could detect cases of unrevealed medium or low level mosaicism in patients tested by Sanger sequencing. Here, we report the first patient with mosaic NOTCH3 gene pathogenic variant to our knowledge; the allelic fraction in the leucocyte DNA was low (13%); the pathogenic variant was inhered by his two daughters. The patient was diagnosed by deep targeted NGS analysis after studying his two affected daughters. This report highlights the importance of parental testing by sensitive tools like deep targeted NGS analysis. Detection of mosaicism is of great importance for diagnosis and adequate family genetic counseling.

The solitary median maxillary central incisor (SMMCI) syndrome: Associations, prenatal diagnosis, and outcomes.

Solitary median maxillary central incisor (SMMCI) syndrome is a complex disorder consisting of multiple, developmental defects involving midline structures of the head, which includes the cranial bones, the maxilla, and its container dentition (specifically the central incisor tooth germ), together with other midline structures of the body. SMMCI may appear as an isolated trait or in association with other midline developmental anomalies. We describe the case of a patient with SMMCI. He presented with a solitary median maxillary incisor, short stature, corpus callosum anomalies and a microform of holoprosencephaly (HPE), diabetes insipidus, and neurodevelopmental delay. The diagnosis was performed postnatally based on clinical features, radiological imaging, and a comprehensive genetic study. SMMCI can be diagnosed during the prenatal or neonatal periods or during infancy. Evaluation of the superior maxillary bone is important for prenatal diagnosis. Direct evaluation through bidimensional ultrasound or the use of multiplanar ultrasound or tridimensional reconstruction should be performed in cases of brain or face malformations. Early diagnosis can contribute to improved prenatal assessment and postnatal management.

Neurofibromatosis type I: mutation spectrum of NF1 in spanish patients.

Neurofibromatosis type I (NF1) is one of the most common genetic disorders in humans. NF1, a tumor predisposition syndrome, is caused by heterozygous pathogenic variants in the NF1 gene. Molecular genetic testing of NF1 is complex, especially because of the presence of a high number of partial pseudogenes, some of them with a high percentage of sequence identity. In this study, we have analyzed the largest cohort of NF1 Spanish patients (150 unrelated individuals suspected of having NF1 and 53 relatives, making a total of 203 individuals). Mutation analysis of the entire coding region was performed in all unrelated index patients. Additionally, the Multiplex Ligation-dependent Probe Amplification (MLPA) test of the NF1 gene and SPRED1 gene analysis (sequencing and MLPA test) was performed in some of the negative patients for NF1 point mutations. When fulfilling the National Institutes of Health (NIH) criterion for the clinical diagnosis of NF1, the detection rate was 79%. Among the 80 genetically confirmed NF1 probands, we detected 69 different pathogenic variants. Two mutations (3%) were gross deletions of the whole gene, the remaining 78 mutations (97%) were small changes spread among all NF1 exons. Among these 69 different mutations detected, 42 mutations were described elsewhere, and 27 mutations were novel mutations. When segregation was studied, 67% of mutations resulted de novo variants. No genetic mosaicism was detected on patients' parents.

Expanding the Phenotypic Spectrum of TRAF7-Related Cardiac, Facial, and Digital Anomalies With Developmental Delay: Report of 11 New Cases and Literature Review.

BACKGROUND: TRAF7-related cardiac, facial, and digital anomalies with developmental delay (CAFDADD), a multisystemic neurodevelopmental disorder caused by germline missense variants in the TRAF7 gene, exhibits heterogeneous clinical presentations. METHODS: We present a detailed description of 11 new TRAF7-related CAFDADD cases, featuring eight distinct variants, including a novel one. RESULTS: Phenotypic analysis and a comprehensive review of the 58 previously reported cases outline consistent clinical presentations, emphasizing dysmorphic features, developmental delay, endocrine manifestations, and cardiac defects. In this enlarged collection, novelties include a wider range of cognitive dysfunction, with some individuals exhibiting normal development despite early psychomotor delay. Communication challenges, particularly in expressive language, are prevalent, necessitating alternative communication methods. Autistic traits, notably rigidity, are observed in the cohort. Also, worth highlighting are hearing loss, sleep disturbances, and endocrine anomalies, including growth deficiency. Cardiac defects, frequently severe, pose early-life complications. Facial features, including arched eyebrows, contribute to the distinct gestalt. A novel missense variant, p.(Arg653Leu), further underscores the complex relationship between germline TRAF7 variants and somatic changes linked to meningiomas. CONCLUSIONS: Our comprehensive analysis expands the phenotypic spectrum, emphasizing the need for oncological evaluations and proposing an evidence-based schedule for clinical management. This study contributes to a better understanding of TRAF7-related CAFDADD, offering insights for improved diagnosis, intervention, and patient care.

A Novel Pathogenic Variant in the MN1 Gene in a Patient Presenting with Rhombencephalosynapsis and Craniofacial Anomalies, Expanding MN1 C-terminal Truncation Syndrome.

Meningioma-1 is a transcription activator that regulates mammalian palate development and is required for appropriate osteoblast proliferation, motility, differentiation, and function. Microdeletions involving the MN1 gene have been linked to syndromes including craniofacial anomalies, such as Toriello-Carey syndrome. Recently, truncating variants in the C-terminal portion of the MN1 transcriptional factor have been linked to a characteristic and distinct phenotype presenting with craniofacial anomalies and partial rhombencephalosynapsis, a rare brain malformation characterized by midline fusion of the cerebellar hemispheres with partial or complete loss of the cerebellar vermis. It has been called MN1 C-terminal truncation (MCTT) syndrome or CEBALID (Craniofacial defects, dysmorphic Ears, Brain Abnormalities, Language delay, and Intellectual Disability) and suggested to be caused by dominantly acting truncated protein MN1 instead of haploinsufficiency. As a proto-oncogene, MN1 is also involved in familial meningioma. In this study, we present a novel case of MCTT syndrome in a female patient presenting with craniofacial anomalies and rhombencephalosynapsis, harboring a de novo pathogenic variant in the MN1 gene: c.3686_3698del, p.(Met1229Argfs*87).

Clinical, Biochemical, and Molecular Characterization of Two Families with Novel Mutations in the LDHA Gene (GSD XI).

Lactate dehydrogenase (LDH) catalyzes the reversible conversion of L-lactate to pyruvate. LDH-A deficiency is an autosomal recessive disorder (glycogenosis type XI, OMIM#612933) caused by mutations in the LDHA gene. We present two young adult female patients presenting with intolerance to anaerobic exercise, episodes of rhabdomyolysis, and, in one of the patients, psoriasis-like dermatitis. We identified in the LDHA gene a homozygous c.410C>A substitution that predicts a p.Ser137Ter nonsense mutation in Patient One and a compound heterozygous c.410C>A (p.Ser137Ter) and c.750G>A (p.Trp250Ter) nonsense mutation in Patient Two. The pathogenicity of the variants was demonstrated by electrophoretic separation of LDH isoenzymes. Moreover, a flat lactate curve on the forearm exercise test, along with the clinical combination of myopathy and psoriatic-like dermatitis, can also lead to the diagnosis.

Fragile X Syndrome Caused by Maternal Somatic Mosaicism of FMR1 Gene: Case Report and Literature Review.

Fragile X syndrome (FXS) is caused by an abnormal expansion of the number of trinucleotide CGG repeats located in the 5' UTR in the first exon of the FMR1 gene. Size and methylation mosaicisms are commonly observed in FXS patients. Both types of mosaicisms might be associated with less severe phenotypes depending on the number of cells expressing FMRP. Although this dynamic mutation is the main underlying cause of FXS, other mechanisms, including point mutations or deletions, can lead to FXS. Several reports have demonstrated that de novo deletions including the entire or a portion of the FMR1 gene end up with the absence of FMRP and, thus, can lead to the typical clinical features of FXS. However, very little is known about the clinical manifestations associated with FMR1 gene deletions in mosaicism. Here, we report an FXS case caused by an entire hemizygous deletion of the FMR1 gene caused by maternal mosaicism. This manuscript reports this case and a literature review of the clinical manifestations presented by carriers of FMR1 gene deletions in mosaicism.

Case report: A novel case of parental mosaicism in SMC1A gene causes inherited Cornelia de Lange syndrome.

Ultimate advances in genetic technologies have permitted the detection of transmitted cases of congenital diseases due to parental gonadosomatic mosaicism. Regarding Cornelia de Lange syndrome (CdLS), up to date, only a few cases are known to follow this inheritance pattern. However, the high prevalence of somatic mosaicism recently reported in this syndrome (∼13%), together with the disparity observed in tissue distribution of the causal variant, suggests that its prevalence in this disorder could be underestimated. Here, we report a new case of parental gonadosomatic mosaicism in SMC1A gene that causes inherited CdLS, in which the mother of the patient carries the causative variant in very low allele frequencies in buccal swab and blood. While the affected child presents with typical CdLS phenotype, his mother does not show any clinical manifestations. As regards SMC1A, the difficulty of clinical identification of carrier females has been already recognized, as well as the gender differences observed in CdLS expressivity when the causal variant is found in this gene. Currently, the use of DNA deep-sequencing techniques is highly recommended when it comes to molecular diagnosis of patients, as well as in co-segregation studies. These enable us to uncover gonadosomatic mosaic events in asymptomatic or oligosymptomatic parents that had been overlooked so far, which might have great implications regarding genetic counseling for recurrence risk.

Hereditary cerebral small vessel disease: Assessment of a HTRA1 variant using protein stability predictors and 3D modelling.

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is an autosomal recessive vascular disorder caused by biallellic variants in HTRA1. Recently, it has been reported that several heterozygous mutations in HTRA1 are responsible for a milder late-onset cerebral small vessel disease (CSVD) with an autosomal dominant pattern of inheritance. The majority of them are missense that affects the Htr1A protease activity due to a dominant-negative effect caused by defective trimerization or monomer activation. The molecular mechanism related to the structural destabilization of the protein supports the practical utility of integrating computational stability predictors to prioritize candidate variants in this gene. In this work, we report a family with several members diagnosed with subcortical ischemic events and progressive cognitive impairment caused by the novel c.820C > G, p.(Arg274Gly) heterozygous variant in HTRA1 segregating in an autosomal dominant manner and propose its molecular mechanism by a three-dimensional model of the protein's structure.

Expanding the clinical and genetic spectrum of SQSTM1-related disorders in family with personality disorder and frontotemporal dementia.

Objective:SQSTM1-variants associated with frontotemporal lobar degeneration have been described recently. In this study, we investigated a heterozygous in-frame duplication c.436_462dup p. (Pro146_Cys154dup) in the SQSTM1 gene in a family with a new phenotype characterized by a personality disorder and behavioral variant frontotemporal dementia (bvFTD). We review the literature on frontotemporal dementia (FTD) associated with SQSTM1. Methods: The index case and relatives were described, and a genetic study through Whole Exome Sequencing was performed. The literature was reviewed using Medline and Web of Science. Case reports, case series, and cohort studies were included if they provided information on SQSTM1 mutations associated with FTD. Results: Our patient is a 70-year-old man with a personality disorder since youth, familial history of dementia, and personality disorders with a 10-year history of cognitive decline and behavioral disturbances. A diagnosis of probable bvFTD was established, and the in-frame duplication c.436_462dup in the SQSTM1 gene was identified. Segregation analysis in the family confirmed that both affected sons with personality disorder were heterozygous carriers, but not his healthy 65-year-old brother. A total of 14 publications about 57 patients with SQSTM1-related FTD were reviewed, in which the bvFTD subtype was the main phenotype described (66.6%), with a predominance in men (63%) and positive family history in 61.4% of the cases. Conclusions: We describe a heterozygous in-frame duplication c.436_462dup p.(Pro146_Cys154dup) in the SQSTM1 gene, which affects the zinc-finger domain of p62, in a family with a personality disorder and bvFTD, expanding the genetics and clinical phenotype related to SQSTM1.

Towards a Change in the Diagnostic Algorithm of Autism Spectrum Disorders: Evidence Supporting Whole Exome Sequencing as a First-Tier Test.

Autism spectrum disorder (ASD) is a prevalent and extremely heterogeneous neurodevelopmental disorder (NDD) with a strong genetic component. In recent years, the clinical relevance of de novo mutations to the aetiology of ASD has been demonstrated. Current guidelines recommend chromosomal microarray (CMA) and a FMR1 testing as first-tier tests, but there is increasing evidence that support the use of NGS for the diagnosis of NDDs. Specifically in ASD, it has not been extensively evaluated and, thus, we performed and compared the clinical utility of CMA, FMR1 testing, and/or whole exome sequencing (WES) in a cohort of 343 ASD patients. We achieved a global diagnostic rate of 12.8% (44/343), the majority of them being characterised by WES (33/44; 75%) compared to CMA (9/44; 20.4%) or FMR1 testing (2/44; 4.5%). Taking into account the age at which genetic testing was carried out, we identified a causal genetic alteration in 22.5% (37/164) of patients over 5 years old, but only in 3.9% (7/179) of patients under this age. Our data evidence the higher diagnostic power of WES compared to CMA in the study of ASD and support the implementation of WES as a first-tier test for the genetic diagnosis of this disorder, when there is no suspicion of fragile X syndrome.

[Leber hereditary optic neuropathy: Usefulness of next generation sequencing to study mitochondrial mutations on apparent homoplasmy]. / Neuropatía óptica de Leber: utilidad de la secuenciación masiva en el estudio de mutaciones mitocondriales en aparente homoplasmia.

BACKGROUND AND OBJECTIVE: Leber hereditary optic neuropathy is characterized by acute and subacute visual loss, produced by mitochondrial DNA mutations. PATIENTS AND METHODS: The molecular study of a family with only one affected member is presented. RESULTS: In the index case and in her mother, the mitochondrial mutation m.11778G>A in the MT-ND4 was detected in the heteroplasmic state. The index case's sister, without ocular manifestations, asked for genetic counseling. The study of the mentioned mutation by Sanger sequencing identified it in an apparent homoplasmic state. However, by means of next-generation sequencing (NGS), the mutation was actually in a heteroplasmic state. CONCLUSIONS: Regarding genetic counseling, verifying a mutation in homoplasmic state is really important. We have observed that NGS allows us to discriminate between high levels of heteroplasmy and homoplasmy, meaning that it is a useful technique for the analysis of apparent homoplasmic results obtained with less sensitive technique, as Sanger sequencing.