Genotype-phenotype Correlation Research Articles

Extending the clinical spectrum of X-linked Tonne-Kalscheuer syndrome (TOKAS): new insights from the fetal perspective

IntroductionTonne-Kalscheuer syndrome (TOKAS) is a recessive X-linked multiple congenital anomaly disorder caused by RLIM variations. Of the 41 patients reported, only 7 antenatal cases were described.MethodAfter the antenatal diagnosis of...

Non-syndromic congenital sideroblastic anaemia; phenotype, and genotype of 15 Indian patients.

Sideroblastic anaemias are a diverse group of congenital and acquired bone marrow failure disorders marked by the presence of ring sideroblasts, ineffective erythropoiesis, and systemic iron overload. Congenital Sideroblastic anaemia (CSA) is mainly caused by gene mutations associated with heme synthesis, iron-sulfur [Fe-S] cluster, and mitochondrial protein synthesis pathways. The most prevalent form of CSA is caused by mutations in the erythroid-specific -amino levulinate synthase (ALAS2) gene, which encodes the first enzyme in the heme synthesis pathway in red blood cells. The second most prevalent form of CSA is caused by a mutation in the Solute carrier family 25 member 38 (SLC25A38) gene, which codes for an erythroid-specific protein of the inner mitochondrial membrane. Additionally, 15-20 genes are altogether associated with CSA. In this study, we aim to identify the CSA patients, understand their genetics and establish genotype-phenotype correlation. We have identified fifteen cases of CSA using our targeted NGS (t-NGS) panel. The major clinical findings in our cohort were microcytic anaemia, ring sideroblasts, and dyserythropoiesis in the bone marrow. Currently, two patients are responsive to pyridoxine, while the rest are on blood transfusion support. We have identified ten variants in three different genes of CSA (ALAS2, SLC25A38 & HSPA9). Five patients harbour four hemizygous variants- p.Ala282Ser, p.Arg170Cys, p.Arg204Gln and exon 2 duplication in the ALAS2 gene. In seven patients, we have identified three homozygous mutations - p.Pro190Arg, p.Arg187Gln and p.Arg134Cys in the SLC25A38 gene. These mutations have been predominantly identified in the European population. Three patients revealed three heterozygous variants p. Thr463Ile, D326Tyr, and Arg284Trp in the HSPA9 gene. PyMoL was used to evaluate the functional effects of these variations and understand their effect on the structure of the protein. We believe that by combining a bone marrow examination with genetic sequencing, CSA patients can acquire a definitive diagnosis.

Inferring disease course from differential exon usage in the wide titinopathy spectrum.

Biallelic titin truncating variants (TTNtv) have been associated with a wide phenotypic spectrum, ranging from complex prenatal muscle diseases with dysmorphic features to adult-onset limb-girdle muscular dystrophy, with or without cardiac involvement. Given the size and complexity of TTN, reaching an unequivocal molecular diagnosis and precise disease prognosis remains challenging. In this case series, 12 unpublished cases and one already published case with biallelic TTNtv were collected from multiple international medical centers between November 2022 and September 2023. TTN mutations were detected through exome or genome sequencing. Information about familial and personal clinical history was collected in a standardized form. RNA-sequencing and analysis of TTN exon usage were performed on an internal sample cohort including postnatal skeletal muscles, fetal skeletal muscles, postnatal heart muscles, and fetal heart muscles. In addition, publicly available RNA-sequencing data was retrieved from ENCODE. We generated new RNA-seq data on TTN exons and identified genotype-phenotype correlations with prognostic implications for each titinopathy patient (whether worsening or improving in prenatal and postnatal life) using percentage spliced in (PSI) data for the involved exons. Interestingly, thanks to exon usage, we were also able to rule out a titinopathy diagnosis in one prenatal case. This study demonstrates that exon usage provides valuable insights for a more exhaustive clinical interpretation of TTNtv; additionally, it may serve as a model for implementing personalized medicine in many other genetic diseases, since most genes undergo alternative splicing.

Microcephaly with or without chorioretinopathy, lymphedema, or mental retardation (MCLMR)- the new lacunae: a case report

BackgroundMicrocephaly with or without chorioretinopathy, lymphedema, or mental retardation is a rare autosomal dominant disease caused by mutations in KIF11 which disrupt EG5 protein function, impacting the development and maintenance of retinal and lymphatic structures due to its expression in the retinal photoreceptor cilia. The primary ocular finding in MCLMR is chorioretinopathy. Additional features can include microphthalmia, angle-closure glaucoma, persistent hyperplastic primary vitreous, cataract, pseudo-coloboma, persistent hyaloid artery, and myopic or hypermetropic astigmatism. The appearance of the chorioretinal lesions as white to pinkish, round, non-elevated atrophic areas devoid of blood vessels resembles the lacunae in Aicardy syndrome. Due to the lack of systematic description of the lesions and significant phenotypical variability, there is an impending need for a detailed report of each case.Case presentationA child with microcephaly detected in the third trimester of gestation began her following in the ophthalmology department due to a non-visually significant cataract. Shortly after, she developed nystagmus and large-angle alternating esotropia with cross-fixation. Her fundus initially showed a pallid optic disc and pigmentary changes, developing thereafter retinal lacunae and a retinal fold. Her differential diagnosis accompanied the dynamic changes in her fundus, which included congenital infections, Leber´s Congenital Amaurosis and Aicardy syndrome. At 19 months old, genetic testing identified a heterozygous mutation (c.1159 C > T, p.Arg387*) in the KIF11 gene. The patient underwent bilateral medial rectus muscle recession surgery at 2 years old for persistent esotropia, with significant improvement. Refraction revealed a hyperopic astigmatism in both eyes (+ 0.25 -2.50 × 180 OD and + 0.75 -2.00 × 170 OS). She continues to require right eye patching for 2 hours daily.ConclusionsThis case report expands the phenotypic spectrum of MCLMR by demonstrating a unique combination of retinal features which sheds new light on differential diagnosis from Aicardy syndrome. Our findings emphasize the significant phenotypic variability associated with MCLMR, particularly regarding ocular involvement. This underscores the importance of detailed clinical evaluation and comprehensive reporting of cases to improve our understanding of the disease spectrum and genotype-phenotype correlations.

Clinical and neuroradiological spectrum of biallelic variants in NOTCH3

NOTCH3 encodes a transmembrane receptor critical for vascular smooth muscle cell function. NOTCH3 variants are the leading cause of hereditary cerebral small vessel disease (SVD). While monoallelic cysteine-involving missense variants in NOTCH3 are well-studied in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), patients with biallelic variants in NOTCH3 are extremely rare and not well characterised. In this study, we present clinical and genetic data from 25 patients with biallelic NOTCH3 variants and conduct a literature review of another 25 cases (50 patients in total). Brain magnetic resonance imaging (MRI) were analysed by expert neuroradiologists to better understand the phenotype associated with biallelic NOTCH3 variants. Our systematic analyses verified distinct genotype-phenotype correlations for the two types of biallelic variants in NOTCH3. Biallelic loss-of-function variants (26 patients) lead to a neurodevelopmental disorder characterised by spasticity, childhood-onset stroke, and periatrial white matter volume loss resembling periventricular leukomalacia. Conversely, patients with biallelic cysteine-involving missense variants (24 patients) fall within CADASIL spectrum phenotype with early adulthood onset stroke, dementia, and deep white matter lesions without significant volume loss. White matter lesion volume is comparable between patients with biallelic cysteine-involving missense variants and individuals with CADASIL. Notably, monoallelic carriers of loss-of-function variants are predominantly asymptomatic, with only a few cases reporting nonspecific headaches. We propose a NOTCH3-SVD classification depending on dosage and variant type. This study not only expands our knowledge of biallelic NOTCH3 variants but also provides valuable insight into the underlying mechanisms of the disease, contributing to a more comprehensive understanding of NOTCH3-related SVD. The Wellcome Trust, the MRC.

Classification of Brain Magnetic Resonance Imaging Abnormalities and Spectrum of Neurological Findings in a Cohort with Copy Number Variation-Related Disorders

Introduction: Copy number variation (CNV) is the difference in the sequence of genomic segments, which can vary from one kilobase to several megabases. Certain CNVs have been linked to various human disorders, such as intellectual disability, multiple congenital anomalies, autism spectrum disorders, neurodegenerative and neuropsychiatric conditions, and cancer. The present study aims to classify brain magnetic resonance imaging (MRI) findings, describe neurological manifestations, and discuss the findings within the context of genotype–phenotype correlations in a cohort of patients with recurrent and nonrecurrent CNVs. Methods: A total of 21 patients with pathogenic CNV detected using microarray analysis were included in the study. Results: Analysis of the clinical findings of the patient cohort showed that 16 (76%) had microcephaly, 14 had epilepsy (66%), 20 had facial dysmorphism (95%), and all had developmental delay (100%). Novel brain MRI findings were detected in six (6/13, 46%) patients with recurrent CNV and five (5/8, 63%) patients with nonrecurrent CNV. Conclusion: CNV-related disorders should be considered in the differential diagnosis of patients with brain MRI findings suspicious for metabolic disorders. Brain MRI differences in patients with the same chromosomal deletion can be explained by the second-hit hypothesis. Additional single nucleotide variations and epigenetic factors in these cases may have led to the involvement of different regions of the brain. Revealing the phenotypic and genotypic characteristics of cases in rare disorders will contribute to the widespread use of precision medicine and genetic treatment approaches in the near future.

Genotype-phenotype correlation over time in Angelman syndrome: Researching 134 patients

Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by the loss of function of maternal UBE3A. The major cause of AS is a maternal deletion in 15q11.2-q13 and the minor causes are a UBE3A mutation, uniparental disomy (UPD) and imprinting defect (ID). Previous reports suggest that all patients with AS exhibit developmental delay, movement or balance disorders, behavioral characteristics and speech impairment. In contrast, a substantial number of AS patients with a UBE3A mutation, UPD or ID were reported not to show these consistent features and to show age dependent change of their features. In this study, we investigated 134 patients with AS, including 57 patients with a UBE3A mutation and 48 patients with UPD or ID. Although developmental delay was present in all patients, 20% of patients with AS caused by UPD or ID did not exhibit movement or balance disorders. Differences were also seen in hypopigmentation and seizures, depending on the causes. Moreover, patients with a UBE3A mutation, UPD or ID tended to show fewer of the specific phenotypes depending on their age. Especially, in patients with UPD or ID, easily-provoked laughter and hyperactivity tended to become more pronounced as they aged. Therefore, the clinical features of AS based on cause and age should be understood and genetic testing should not be limited to patients with the typical clinical features of AS.

Evaluating precision medicine approaches for gene therapy in patient-specific cellular models of Bietti crystalline dystrophy.

Patient-specific induced pluripotent stem cell-derived (iPSC-derived) cell lines allow for therapies to be tailored to individual patients, increasing therapeutic precision and efficiency. Bietti crystalline dystrophy (BCD) is a rare blinding disease estimated to affect about 67,000 individuals worldwide. Here, we used iPSC-derived retinal pigment epithelium (iRPE) cells from patients with BCD to evaluate adeno-associated virus-mediated (AAV-mediated) gene augmentation therapy strategies. We found that BCD iRPE cells were vulnerable to blue light-induced oxidative stress and that cellular phenotype can be quantified using 3 robust biomarkers: reactive oxygen species (ROS), 4-hydroxy 2-nonenal (4-HNE) levels, and cell death rate. Additionally, we demonstrated that AAV-mediated gene therapy can significantly reduce light-induced cell death in BCD iRPE cells. This is the first proof-of-concept study to our knowledge to show that AAV-CYP4V2 gene therapy can be used to treat light-induced RPE damage in BCD. Furthermore, we observed significant variability in cellular phenotypes among iRPE from patients with BCD of divergent mutations, which outlined genotype-phenotype correlations in BCD patient-specific cell disease models. Our results reveal that patient-specific iRPE cells retained personalized responses to AAV-mediated gene therapy. Therefore, this approach can advance BCD therapy and set a precedent for precision medicine in other diseases, emphasizing the necessity for personalization in healthcare to accommodate individual diversity.

Hydrops fetalis due to loss of function of hNav1.4 channel via compound heterozygous variants.

Hydrops fetalis, characterized by abnormal fluid accumulation in fetuses, presents a significant risk of stillbirth and neonatal mortality. Although the etiology of nonimmune hydrops fetalis (NIHF) is multifaceted, recent studies have highlighted genetic factors as crucial determinants. This study focused on a family with three consecutive stillbirths, each with pronounced hydrops fetalis. Using whole-exome sequencing (WES), we identified compound heterozygous variants of the SCN4A gene encoding the voltage-gated sodium channel of the skeletal muscle (hNav1.4), c.2429T>A p.L810Q and c.4556T>C p.F1519S, in all three deceased infants. A functional analysis conducted using the whole-cell patch-clamp technique revealed loss-of-function defects in both variant channels, with F1519S exhibiting a complete loss of ionic current and L810Q showing a reduced channel opening. These findings support the pathogenicity of SCN4A variants in NIHF and underscore the significance of functional studies in elucidating genotype-phenotype correlations. Furthermore, our study emphasizes the diagnostic value of WES in cases of NIHF in where standard genetic testing fails to identify causative variants.

Identification of biallelic mutations in MCM3AP and comprehensive literature analysis.

Minichromosome maintenance complex component 3 associated protein (MCM3AP) is a gene in which mutations can result in autosomal recessive peripheral neuropathy with or without impaired intellectual development. The MCM3AP genotype-phenotype correlation and prognosis remain unclear. The aim of this study was to explore the genotype-phenotype correlations pertaining to MCM3AP. Whole-exome sequencing (WES) combined with copy number variation sequencing (CNV-seq) were performed on the genomic DNA isolated from a Chinese family, and Sanger sequencing, quantitative PCR and cDNA analyses were performed to examine the mutations. The retrospective study was conducted on 28 individuals with biallelic MCM3AP mutation-related diseases, including features such as mutations, motor development impairment, intellectual disability, weakness/atrophy, and cerebral magnetic resonance imaging abnormalities. Sequencing identified novel compound heterozygous mutations in MCM3AP, namely, a paternal variant c.1_5426del (loss of exons 1-25) and a maternal splicing variant c.1858 + 3A>G. Functional studies revealed that the variant c.1858 + 3A>G resulted in the heterozygous deletion of exon 5, thereby affecting splicing functionality. Furthermore, the compound heterozygous mutation may affect the functionality of the protein domain. Retrospective analysis revealed different genotype-phenotype correlations for the pathogenic variants in biallelic MCM3AP: all individuals (100%) with mutations outside the Sac3 domain exhibited early-onset symptoms, motor developmental delays, and cognitive abnormalities, conversely, the proportions of individuals carrying mutations within the domain were 26.7% (motor delays) and 46.7% (cognitive abnormalities). Our findings further expand the genetic mutation spectrum of biallelic MCM3AP and highlight the genotype-phenotype associations. Additionally, we elaborate on the importance of rehabilitation intervention.

POLR3B de novo variants are a rare cause of infantile myoclonic epilepsy

PurposeTo report on a new phenotype in a patient carrying a novel, undescribed de novo variant in POLR3B, affected by generalized myoclonic epilepsy and neurodevelopmental disorder, without neuropathy. It is known that biallelic pathogenic variants in POLR3B cause hypomyelinating leukodystrophy-8, and heterozygous de novo variants are described in association to a phenotype characterized by predominantly demyelinating sensory-motor peripheral neuropathy, ataxia, spasticity, intellectual disability and epilepsy, in which the peripheral neuropathy is often the main clinical presentation. MethodsWe collected clinical, electrophysiological and neuroimaging data from the affected subject and performed a Trio-Clinical Exome Sequencing. ResultsWe detected a de novo novel heterozygous missense variant c.1132A>G in POLR3B (NM_018082.6) that was considered as likely pathogenic following ACMG criteria. We also consulted our custom genomic database of a total of 1485 patients that were genetically analysed from 2018 for epilepsy, and found no other de novo variants in the POLR3B gene. ConclusionWe hypothesize a possible genotype-phenotype correlation, particularly regarding epilepsy. We also provide a review of the literature about the previously described POLR3B heterozygous patients, with particular attention to the epileptic phenotype, underlining the association between POLR3B and early onset myoclonic epilepsy, which can represent the main manifestation of the disease at its onset.

Clinical characteristics and genetic profile of children with WDR72-associated distal renal tubular acidosis: a nationwide experience.

Limited data, primarily from small case series, exist regarding the clinical profile, genetic variants, and outcomes of WDR72-associated distal renal tubular acidosis (WDR72-dRTA). Our study enrolled children diagnosed with WDR72-dRTA below 18years of age from 9 Indian centers and analyzed their clinical characteristics, genetic profiles, and outcomes. Potential genotype-phenotype correlations were explored. We report 22 patients (59% female) with WDR72-dRTA who were diagnosed at a median age of 5.3 (3, 8) years with polyuria (n = 17; 77.3%), poor growth (16; 72.7%), and rickets (9; 40.9%). Amelogenesis imperfecta was present in 21 (95.5%) cases. At presentation, all patients had normal anion gap metabolic acidosis; hypokalemia and nephrocalcinosis were seen in 17 (77.3%) patients each. Seven (31.8%) patients had concomitant proximal tubular dysfunction. Genetic analysis identified biallelic nonsense variants in 18 (81.8%) patients, including novel variants in 6 cases. A previously reported variant, c.88C > T, and a novel variant, c.655C > T, were the most frequent variants, accounting for 10 (45.5%) cases. Over a median follow-up of 1.3 (1, 8) years, the height velocity improved by 0.74 (0.2, 1.2) standard deviation scores, while 3 children (13.6%) progressed to chronic kidney disease (CKD) stage 2, with eGFR ranging from 67 to 76mL/min/1.73 m2, respectively, after 11.3-16years of follow-up. No specific genotype-phenotype correlation could be established. WDR72-dRTA should be considered in children with typical features of amelogenesis imperfecta and dRTA. Biallelic nonsense variants are common in Asians. While most patients respond well to treatment with improved growth and preserved eGFR, on long-term follow-up, a decline in eGFR may occur.

Intermediate phenotype between CMT2Z and DIGFAN associated with a novel MORC2 variant: a case report

Charcot-Marie-Tooth disease type 2Z is caused by MORC2 mutations and presents with axonal neuropathy. MORC2 mutations can also manifest as developmental delay, impaired growth, dysmorphic facies, and axonal neuropathy (DIGFAN). We report a patient exhibiting an intermediate phenotype between these diseases associated with a novel MORC2 variant. A literature review revealed that the genotype‒phenotype correlation in MORC2-related disorders is complex and that the same mutation can cause a variety of phenotypes.

Clinical and genetic characteristics of Chinese patients with congenital fibrosis of the extraocular muscles

ObjectiveThis study aimed to describe the clinical and genetic characteristics of Chinese patients with congenital fibrosis of the extraocular muscles (CFEOM), and to evaluate the phenotype–genotype correlations in these patients.MethodsThis was a retrospective study. Patients with CFEOM underwent detailed ophthalmic examinations and magnetic resonance imaging (MRI). Panel-based next-generation sequencing was performed to identify pathogenic variants of disease-causing genes.ResultsSixty-two patients with CFEOM were recruited into this study. Thirty-nine patients were diagnosed with CFEOM1 and 23 with CFEOM3. Forty-nine of the 62 patients with CFEOM carried either KIF21A (41/49) or TUBB3 variants (8/49). Six known missense variants in the KIF21A and TUBB3 genes, and a novel variant (c.3906T > A, p.D1302E) in the KIF21A gene were detected. Most patients with CFEOM1 carrying the KIF21A mutation displayed isolated CFEOM, whereas patients with CFEOM3 carrying the TUBB3 mutation had a wide range of clinical manifestations, either CFEOM alone or syndromes. Nystagmus was also present in 12 patients with CFEOM. Furthermore, the MRI findings varied, ranging from attenuation of the extraocular muscles to dysgenesis of the cranial nerves and brain structure.ConclusionsThe novel variants identified in this study will further expand the spectrum of pathogenic variants in CFEOM-related genes. However, no phenotype–genotype correlations were established because of the diversity of the clinical characteristics of these patients.

Automated Craniofacial Biometry with 3D T2w Fetal MRI.

Evaluating craniofacial phenotype-genotype correlations prenatally is increasingly important; however, it is subjective and challenging with 3D ultrasound. We developed an automated landmark propagation pipeline using 3D motion-corrected, slice-to-volume reconstructed (SVR) fetal MRI for craniofacial measurements. A literature review and expert consensus identified 31 craniofacial biometrics for fetal MRI. An MRI atlas with defined anatomical landmarks served as a template for subject registration, auto-labelling, and biometric calculation. We assessed 108 healthy controls and 24 fetuses with Down syndrome (T21) in the third trimester (29-36 weeks gestational age, GA) to identify meaningful biometrics in T21. Reliability and reproducibility were evaluated in 10 random datasets by four observers. Automated labels were produced for all 132 subjects with a 0.03% placement error rate. Seven measurements, including anterior base of skull length and maxillary length, showed significant differences with large effect sizes between T21 and control groups (ANOVA, p<0.001). Manual measurements took 25-35 minutes per case, while automated extraction took approximately 5 minutes. Bland-Altman plots showed agreement within manual observer ranges except for mandibular width, which had higher variability. Extended GA growth charts (19-39 weeks), based on 280 control fetuses, were produced for future research. This is the first automated atlas-based protocol using 3D SVR MRI for fetal craniofacial biometrics, accurately revealing morphological craniofacial differences in a T21 cohort. Future work should focus on improving measurement reliability, larger clinical cohorts, and technical advancements, to enhance prenatal care and phenotypic characterisation.

MODY Only Monogenic? A Narrative Review of the Novel Rare and Low-Penetrant Variants.

Maturity-onset diabetes of the young (MODY) represents the most frequent form of monogenic diabetes mellitus (DM), currently classified in 14 distinct subtypes according to single gene mutations involved in the differentiation and function of pancreatic β-cells. A significant proportion of MODY has unknown etiology, suggesting that the genetic landscape is still to be explored. Recently, novel potentially MODY-causal genes, involved in the differentiation and function of β-cells, have been identified, such as RFX6, NKX2.2, NKX6.1, WFS1, PCBD1, MTOR, TBC1D4, CACNA1E, MNX1, AKT2, NEUROG3, EIF2AK3, GLIS3, HADH, and PTF1A. Genetic and clinical features of MODY variants remain highly heterogeneous, with no direct genotype-phenotype correlation, especially in the low-penetrant subtypes. This is a narrative review of the literature aimed at describing the current state-of-the-art of the novel likely MODY-associated variants. For a deeper understanding of MODY complexity, we also report some related controversies concerning the etiological role of some of the well-known pathological genes and MODY inheritance pattern, as well as the rare association of MODY with autoimmune diabetes. Due to the limited data available, the assessment of MODY-related genes pathogenicity remains challenging, especially in the setting of rare and low-penetrant subtypes. In consideration of the crucial importance of an accurate diagnosis, prognosis and management of MODY, more studies are warranted to further investigate its genetic landscape and the genotype-phenotype correlation, as well as the pathogenetic contribution of the nongenetic modifiers in this cohort of patients.

Genetic Diagnostic Yield in Autism Spectrum Disorder (ASD) and Epilepsy Phenotypes in Children with Genetically Defined ASD.

We compared the epilepsy phenotypes in children with genetically defined versus undefined autism spectrum disorder (ASD). A single-center retrospective study was conducted to investigate diagnostic yields of different genetic testing for children with ASD. Patients with at least one testing modality were included and classified as having genetically defined ASD or not based on updated genotype-phenotype correlation. Of the 523 patients included, 79 (15.1%) had results explaining their ASD diagnosis. WES (whole exome sequencing) outperformed CMA (chromosomal microarray) on diagnostic yield (23.0% versus 8.3%). Compared to those with non-diagnostic test(s), children with genetically defined ASD were associated with higher rates for microcephaly, hypotonia, dysmorphic features, and developmental delay/regression. The prevalence of epilepsy was significantly higher in children with genetically defined ASD than those without a genetic diagnosis (35.4% versus 16.4%, p < 0.001, power = 0.97). Furthermore, children with genetically defined ASD had a younger age of epilepsy onset (median 2.2 versus 5.0years, p = 0.002, power = 0.90) and a higher rate of drug-resistant epilepsy although not reaching statistical significance (35.7% versus 21.9%, p = 0.20). Our study has provided further evidence to support WES as first-tier test for children with ASD and that an early genetic diagnosis has the potential to inform further surveillance and management for ASD comorbid conditions including epilepsy.

Genotype and X-chromosome inactivation are associated with disease severity in females with X-linked Alport syndrome.

Male patients with X-linked Alport syndrome (XLAS) generally develop end-stage kidney disease in early or middle adulthood and show distinct genotype-phenotype correlations. Female patients, however, show various phenotypes ranging from asymptomatic to severe with no genotype-phenotype correlations. However, the factors affecting the severity of XLAS in female patients are unclear. Since X-chromosome inactivation (XCI) affects the severity of certain female X-linked diseases, we investigated whether genotype and XCI were associated with XLAS severity in female patients in a large Japanese cohort. Among 139 female patients with genetically diagnosed XLAS at our institution, we conducted XCI analysis on peripheral blood leukocytes using the human androgen receptor assay method and analyzed two cohorts. In 74 adult female patients, we evaluated the correlation between kidney function (creatinine-estimated glomerular filtration rate [Cr-eGFR] optimized for Japanese individuals) and genotype/XCI using multivariable linear regression analysis, and in 65 pediatric female patients, we evaluated the correlation between kidney function (Cr-eGFR optimized for Japanese individuals) and genotype/XCI using multivariable linear regression analysis. We also investigated the correlation between the development of proteinuria (urine protein-to-creatinine ratio above normal for the patient's age) and genotype/XCI using multivariable Cox proportional hazard analysis. In adult female patients, XCI pattern was significantly associated with Cr-eGFR (regression coefficient estimate = -0.53, P=0.004), whereas genotype was not (P=0.892). In pediatric female patients, both genotype and XCI pattern were significant independent risk factors for the development of proteinuria (hazard ratio [HR], 3.702; 95% confidence interval [CI], 1.681-8.150; P=0.001 and HR, 1.043; 95% CI, 1.061-1.070; P=0.001, respectively), whereas both genotype and XCI pattern were not associated with Cr-eGFR (P=0.20, P=0.67, respectively). Genotype and XCI are factors associated with the severity in females with XLAS.

Abstract Introduction of a novel pathogenic variant (c.1684G&gt;A) in the SOX5 gene associated with Lamb– Shaffer syndrome in a family from north of Iran

So far, different types of SOX5 variants have been reported in patients with LAMSHF syndrome, which are mainly clustered in the HMG domain. The LAMSHF syndrome has a broad variety of clinical manifestations such as developmental delay, speech delay, intellectual disability, and behavioral disturbances. In this article, we aim to present three cases with Lamb–Shaffer syndrome who are heterozygotes for a novel variant (c.1684G&gt;A) in the SOX5 gene in a family from the north of Iran. A 38-year-old male case with moderate mental retardation and strabismus, with a head circumference size of 56 cm, was tested for genetic diagnosis. The results of wholeexome sequencing (WES) indicated the c.1684G&gt;A pathogenic variant (NM_006940.6) in the SOX5 gene in a heterozygote state. Family analysis showed that the proband’s sister and father, who have similar symptoms, also carry the detected variant. Like the previous cases, the presented cases with a missense variant in the HMGdomain also have a mild phenotype. The introduction of new patients, especially with new pathogenic variants, is fundamental to increasing our knowledge about the disease and possible genotype–phenotype correlations.

Genotype is associated with left ventricular reverse remodelling and early events in recent-onset dilated cardiomyopathy.

Recent-onset dilated cardiomyopathy (RODCM) is characterized by heterogeneous aetiology and diverse clinical outcomes, with scarce data on genotype-phenotype correlates. Our aim was to correlate individual RODCM genotypes with left ventricular reverse remodelling (LVRR) and clinical outcomes. In this prospective study, a total of 386 Czech RODCM patients with symptom duration ≤6months underwent genetic counselling and whole-exome sequencing (WES). The presence of pathogenic (class 5) or likely pathogenic (class 4) variants in a set of 72 cardiomyopathy-related genes was correlated with the occurrence of all-cause death, heart transplantation, or implantation of a ventricular assist device (primary outcome) and/or ventricular arrhythmia event (secondary outcome). LVRR was defined as an improvement of left ventricular ejection fraction to >50% or ≥10% absolute increase, with a left ventricular end-diastolic diameter ≤33mm/m2 or ≥10% relative decrease. Median follow-up was 41months. RODCM was familial in 98 (25%) individuals. Class 4-5 variants of interest (VOIs) were identified in 125 (32%) cases, with 69 (18%) having a single titin-truncating variant (TTNtv) and 56 (14%) having non-titin (non-TTN) VOIs. The presence of class 4-5 non-TTN VOIs, but not of TTNtv, heralded a lower probability of 12-month LVRR and proved to be an independent baseline predictor both of the primary and the secondary outcome. The negative result of genetic testing was a strong protective baseline variable against occurrence of life-threatening ventricular arrhythmias. Detection of class 4-5 VOIs in genes coding nuclear envelope proteins was another independent predictor of both study outcomes at baseline and also of life-threatening ventricular arrhythmias after 12months. Class 4-5 VOIs of genes coding cytoskeleton were associated with an increased risk of life-threatening ventricular arrhythmias after baseline assessment. A positive family history of dilated cardiomyopathy alone only related to a lower probability of LVRR at 12months and at the final follow-up. RODCM patients harbouring class 4-5 non-TTN VOIs are at higher risk of progressive heart failure and life-threatening ventricular arrhythmias. Genotyping may improve their early risk stratification at baseline assessment.