Genetikum

Introduction: Tuberous sclerosis complex (TSC) is a neurocutaneous disorder caused by pathogenic variants in the TSC1 or TSC2 genes and exhibits marked phenotypic variability. Although TSC2 variants are typically associated with more severe clinical manifestations, certain missense alterations may lead to mild and limited phenotypes. In this report, we describe a family in which the heterozygous TSC2 (NM_000548.5): c.3061G>A, p.(Glu1021Lys) variant was identified in three individuals, and we present the associated mild, atypical, and variable clinical features in these patients. Case Presentation: Clinical evaluations, neuroimaging (brain MRI), and genetic analyses were conducted in the proband and family members. Segregation analysis of the identified variant was performed in the mother and one sibling. Findings were compared with previously reported mild TSC2 missense variants in the literature. The proband exhibited neurodevelopmental delay, treatment-resistant epilepsy, hypopigmented macules, and EEG abnormalities. Whole-exome sequencing revealed the TSC2 (NM_000548.5): c.3061G>A (p.Glu1021Lys) variant in a heterozygous state. Sanger sequencing confirmed the same heterozygous variant in the mother and in one sibling, both of whom had hypopigmented macules. Other family members suspected of having TSC also demonstrated limited cutaneous features but were not genetically tested due to family preference. None of the affected individuals showed cortical tubers, subependymal nodules (SEN), or subependymal giant cell astrocytoma (SEGA) on neuroimaging. Likewise, there was no evidence of renal involvement (angiomyolipoma) or cardiac rhabdomyoma—typical major features of TSC. The phenotypic distribution was characterized by predominant cutaneous findings, mild neurological involvement, and minimal imaging abnormalities. Conclusion: The phenotype observed in this family suggests that the TSC2 c.3061G>A (p.Glu1021Lys) variant may be associated with a mild TSC2 missense presentation. Although notable intrafamilial heterogeneity was present, the absence of SEN, SEGA, renal, and cardiac manifestations—combined with predominantly cutaneous findings—is consistent with previously described mild TSC2 variant patterns. These observations highlight the importance of clinical surveillance in carriers and emphasize that mild TSC2 phenotypes may be easily overlooked in diagnostic evaluations. Keywords: Tuberous sclerosis, TSC2, p.Glu1021Lys, subependymal nodule, SEGA, mild phenotype, missense variant, intrafamilial heterogeneity

Cilia are thin extensions on the cells of eukaryotic organisms. They are formed by a special protein transport mechanism - the intraflagellar transporter (IFT). The IFT consists of two proteins: complex A and complex B. Mutations in the genes of the IFT-A complex (IFT43, IFT121, IFT122, IFT139, IFT140, and IFT144) lead to the development of skeletal ciliopathies. These include Sensenbrenner, Jeune, and short-rib polydactyly syndrome [1,2]. We report two cases of different ciliopathies in a non-related family; both parents are heterozygous carriers of a pathogenic mutation in the IFT122 gene.

Pathogenic ANKH variants are a known cause of chondrocalcinosis (Online Mendelian Inheritance in Man [OMIM] #118600) and craniometaphyseal dysplasia (OMIM #123000). Here, we describe the phenotype and genotype of autosomal dominant infantile epilepsy caused by a c.-11C>T change upstream of the gene's normal ATG initiation codon of ANKH in a family of southern Italian descent; we correlate the phenotype with known epilepsy syndromes and provide the first evidence of recurrence of this particular ANKH variant. Phenotyping and genotyping (short-read exome/genome sequencing) was performed on six members of a family with self-limited familial infantile epilepsy (SeLFIE). We describe a family with six individuals who presented with infantile onset epilepsy. All affected family members experienced focal and/or bilateral tonic-clonic seizures, sometimes triggered by fever or infection, with seizure onset predominantly before the age of 2 years. Patients responded well to antiseizure medication, and seizures resolved completely before the age of 4 years. Short-read genome/exome sequencing and comparative bioinformatic analysis of the variants of five affected individuals and one unaffected individual revealed ANKH c.-11C>T as the causative pathogenic variant in this family, segregating with the disease. To our knowledge, we report the second family with autosomal dominant epilepsy caused by an ANKH c.-11C>T variant. The pediatric phenotype closely resembles that of the previously reported British family, suggesting low phenotypic heterogeneity, and aligns with SeLFIE. ANKH-associated epilepsy should be considered in SeLFIE, especially in cases with a family history of chondrocalcinosis or recurrent acute joint pain episodes.

This study aimed to evaluate KRAS and NRAS mutations over an eight‐year period to provide a comprehensive understanding of the genetic landscape of metastatic colorectal cancer (mCRC) in Turkish patients. Tumor tissue samples were collected from 10 754 patients with mCRC between January 2015 and June 2023 from multiple centers across Turkey, and all genetic analyses were performed at a single facility. DNA was analyzed for mutations in codons 12, 13, 59, 61, 117, and 146 of the KRAS and NRAS genes using nested PCR and multiplex minisequencing techniques. Among the conclusive results from 10 681 patients, 46.6% (4982) had KRAS mutations, and 53.4% (5699) were wild‐type. The most common KRAS mutations were G12D (30.3%), G12V (20.1%), G13D (18.4%), and G12C (7.0%). Results from the 5699 KRAS wild‐type patients revealed that 480 (8.5%) had NRAS mutations, while 91.5% were NRAS wild‐type. The most frequent NRAS mutations were Q61K (19.7%), G12D (19.1%), and G12V (12%). This study provides a large‐scale, real‐world dataset of KRAS and NRAS mutation profiles in Turkish mCRC patients, contributing significantly to the understanding of the genetic characteristics of mCRC in this population.

Abstract Patients with acute decompensation (AD) of cirrhosis face a high risk of acute-on-chronic liver failure (ACLF), a syndrome linked to multiple organ failure and high mortality. This study analyzed peripheral blood mononuclear cells (PBMCs) using single-cell technologies to explore their role in patient outcomes. Blood samples from 15 healthy donors and 63 AD patients were prospectively collected at hospital admission across five European centers, with patients monitored for 90 days. CITE-seq was performed on PBMCs from 4 controls and 16 patients representing different disease trajectories. A rise in classical monocytes, particularly subcluster “C2,” was noted in patients progressing to ACLF. This subset showed impaired energy metabolism, with reduced oxidative phosphorylation and ATP production. Notably, genes coding for Complex IV of the respiratory chain were significantly downregulated. In two large prospective international cohorts (PREDICT, n=689; ACLARA, n=521), we observed that a gene signature from C2 was elevated in patients with cirrhosis with bacterial infections, ACLF, and in non-survivors. Functional validation of our findings was performed using respirometry analyses in an independent AD cohort, specifically evaluating mitochondrial function in the total classical monocyte population. A progressive decline in Complex IV-driven oxygen consumption rate (OCR) was observed in pre-ACLF patients. In conclusion, we idenofied and validated that paoents with AD having a poor outcome are characterized by a subpopulaoon of monocytes with impaired energy metabolism. This cell populaoon might contribute to the transioon from AD to ACLF.TeaserA unique monocyte subset with metabolic dysfunction is associated with disease progression in patients with acute decompensation of cirrhosis.

Giriş: CACNA1E geni, voltaj kapılı R-tipi kalsiyum kanalının α1E alt birimini kodlamakta olup, bu gendeki de novo varyantlar erken başlangıçlı gelişimsel ve epileptik ensefalopati ile ilişkilidir (OMIM:618285). Olgu Sunumu: Bu çalışmada erken çocuklukta başlayan epileptik nöbetleri, yaşına uygun nörogelişim basamağı, EEG’de bilateral fronto-sentral epileptiform aktivitesi olan bir vaka değerlendirilmiş ve yapılan tüm ekzom dizileme çalışmasında CACNA1E geninin 30. ekzonunda yer alan ve erken dur kodonu oluşmasına neden olan heterozigot nonsense c.4165C>T (p.Arg1389*) varyantı de novo olarak saptanmıştır. Sonuç: Hastamızdaki bulguların göreceli olarak hafif olması ve nörogelişimsel basamakların normal olması, CACNA1E genindeki fonksiyon kaybına neden olan varyantların, literatürde tanımlanan fonksiyon kazanımı yapan varyantlara göre daha hafif klinik fenotiplere yol açabileceği görüşünü desteklemektedir. CACNA1E geni için genotip-fenotip ilişkisinin tam olarak anlaşılabilmesi için daha geniş hasta serilerine ve çok merkezli çalışmalara ihtiyaç vardır. Anahtar Sözcükler: CACNA1E geni, epileptik ensefalopati, fonksiyon kaybı varyantı, genotip-fenotip korelasyonu

During the latter half of the twentieth century we came to understand that DNA was Schrödinger's ‚code-script', deciphered its complex message, and began to figure out precisely how it guides the processes of life. This epic adventure in understanding would mark the birth of a new era of science, one that lay at the nexus of biology and technology.1 Craig Venter Die Biologie musste den Sprung zur Molekularbiologie machen, in der das verstreute Leben sich im genetischen Code zusammenfasst.2

Epilepsy is one of the most common and disabling neurological disorders. It is highly prevalent in children with neurodevelopmental delay and syndromic diseases. However, epilepsy can also be the only disease-determining symptom. The exact molecular diagnosis is essential to determine prognosis, comorbidity, and probability of recurrence, and to inform therapeutic decisions. Here, we describe a prospective cohort study of patients with epilepsy evaluated in seven diagnostic outpatient centers in Germany. Over a period of 2 months, 07/2022 through 08/2022, 304 patients (317 returned result) with seizure-related human phenotype ontology (HPO) were analyzed. Evaluated data included molecular results, phenotype (syndromic and non-syndromic), and sequencing methods. Single exome sequencing (SE) was applied in half of all patients, followed by panel (P) testing (36%) and trio exome sequencing (TE) (14%). Overall, a pathogenic variant (PV) (ACMG cl. 4/5) was identified in 22%; furthermore, a significant number of patients (12%) carried a reported clinically meaningful variant of unknown significance (VUS). The average diagnostic yield in patients ≤ 12 y was higher compared to patients >12 y cf. Figure 2B vs. Figure 3B. This effect was more pronounced in cases, where TE was applied in patients ≤ 12 vs. >12 y [PV (PV + VUS): patients ≤ 12 y: 35% (47%), patients > 12 y: 20% (40%)]. The highest diagnostic yield was achieved by TE in syndromic patients within the age group ≤ 12 y (ACMG classes 4/5 40%). In addition, TE vs. SE had a tendency to result in less VUS in patients ≤ 12 y [SE: 19% (22/117) VUS; TE: 17% (6/36) VUS] but not in patients >12 y [SE: 19% (8/42) VUS; TE: 20% (2/10) VUS]. Finally, diagnostic findings in patients with syndromic vs. non-syndromic symptoms revealed a significant overlap of frequent causes of monogenic epilepsies, including SCN1A, CACNA1A, and SETD1B, confirming the heterogeneity of the associated conditions. In patients with seizures-regardless of the detailed phenotype-a monogenic cause can be frequently identified, often implying a possible change in therapeutic action (36.7% (37/109) of PV/VUS variants); this justifies early and broad application of genetic testing. Our data suggest that the diagnostic yield is highest in exome or trio-exome-based testing, resulting in a molecular diagnosis within 3 weeks, with profound implications for therapeutic strategies and for counseling families and patients regarding prognosis and recurrence risk.