Longitudinal Structure-Function Evaluation in a Patient with CDHR1-Associated Retinal Dystrophy: Progressive Visual Function Loss with Retinal Remodeling.

BACKGROUND: Retinal dystrophies related to damaging variants in the cadherin-related family member 1 (CDHR1) gene are rare and phenotypically heterogeneous. Here, we report a longitudinal (three-year) structure-function evaluation of a patient with a CDHR1-related retinal dystrophy. METHODS: A 14-year-old girl was evaluated between 2019 and 2022. An ophthalmological assessment, including color vision, perimetry, electroretinography, and multimodal imaging of the retina, was performed periodically every six months. Next-generation sequencing disclosed two likely pathogenic/pathogenic variants in the CDHR1 gene, in compound heterozygosity, confirmed by segregation analysis. RESULTS: At first examination, the patient showed a cone-rod pattern retinal dystrophy. Over follow-up, there was a decline of visual acuity and perimetric sensitivity (by ≥0.3 and 0.6 log units, respectively). Visual loss was associated with a progressive increase in inner retinal thickness (by 30%). Outer retina showed no detectable changes over the follow-up. CONCLUSIONS: The results indicate that, in this patient with a CDHR1-related cone-rod dystrophy, the progression to severe visual loss was paralleled by a progressive inner retinal thickening, likely a reflection of remodeling. Inner retinal changes over time may be functionally relevant in view of the therapeutic attempts based on gene therapy or stem cells to mitigate photoreceptor loss.

Relationship between Nutrition, Lifestyle, and Neurodegenerative Disease: Lessons from ADH1B, CYP1A2 and MTHFR.

In the present review, the main features involved in the susceptibility and progression of neurodegenerative disorders (NDDs) have been discussed, with the purpose of highlighting their potential application for promoting the management and treatment of patients with NDDs. In particular, the impact of genetic and epigenetic factors, nutrients, and lifestyle will be presented, with particular emphasis on Alzheimer's disease (AD) and Parkinson's disease (PD). Metabolism, dietary habits, physical exercise and microbiota are part of a complex network that is crucial for brain function and preservation. This complex equilibrium can be disrupted by genetic, epigenetic, and environmental factors causing perturbations in central nervous system homeostasis, contributing thereby to neuroinflammation and neurodegeneration. Diet and physical activity can directly act on epigenetic modifications, which, in turn, alter the expression of specific genes involved in NDDs onset and progression. On this subject, the introduction of nutrigenomics shed light on the main molecular players involved in the modulation of health and disease status. In particular, the review presents data concerning the impact of ADH1B, CYP1A2, and MTHFR on the susceptibility and progression of NDDs (especially AD and PD) and how they may be exploited for developing precision medicine strategies for the disease treatment and management.

Possible Role of the RORC Gene in Primary and Secondary Lymphedema: Review of the Literature and Genetic Study of Two Rare Causative Variants.

Background: RAR-related Orphan Receptor C (RORC) is a DNA-binding transcription factor and the key transcription factor responsible for differentiation of T helper 17 cells. The RORC gene plays a role in lymphoid organogenesis, thymopoiesis, and lymph node organogenesis. The aim of our study was to determine the possible role of RORC in the development of lymphatic system malformations by combining data from the scientific literature and next-generation sequencing of RORC in lymphedema patients negative for known causative genes. Methods and Results: We sequenced RORC in 235 lymphedema patients negative for known lymphedema-associated genes. We found two probands carrying nonsense RORC variants. Conclusions: We show that RORC is important for normal function of the lymphatic system and that a rare variant with a possible causative effect may imply predisposition for lymphedema.

NOTCH1: Review of its role in lymphatic development and study of seven families with rare pathogenic variants.

BACKGROUND: We developed a Next-Generation-Sequencing (NGS) protocol to screen the most frequent genetic variants related to lymphedema and a group of candidate genes. The aim of the study was to find the genetic cause of lymphedema in the analyzed patients. METHODS: We sequenced a cohort of 246 Italian patients with lymphatic malformations. In the first step, we analyzed genes known to be linked to lymphedema: 235 out of 246 patients tested negative for the most frequent variants and underwent testing for variants in a group of candidate genes, including the NOTCH1 gene, selected from the database of mouse models. We also performed in silico analysis to observe molecular interactions between the wild-type and the variant amino acids and other protein residues. RESULTS: Seven out of 235 probands, five with sporadic and two with familial lymphedema, were found to carry rare missense variants in the NOTCH1 gene. CONCLUSIONS: Our results propose that NOTCH1 could be a novel candidate for genetic predisposition to lymphedema.

Investigation of Genetic Variations of IL6 and IL6R as Potential Prognostic and Pharmacogenetics Biomarkers: Implications for COVID-19 and Neuroinflammatory Disorders.

In the present study, we investigated the distribution of genetic variations in IL6 and IL6R genes, which may be employed as prognostic and pharmacogenetic biomarkers for COVID-19 and neurodegenerative diseases. The study was performed on 271 samples representative of the Italian general population and identified seven variants (rs140764737, rs142164099, rs2069849, rs142759801, rs190436077, rs148171375, rs13306435) in IL6 and five variants (rs2228144, rs2229237, rs2228145, rs28730735, rs143810642) within IL6R, respectively. These variants have been predicted to affect the expression and binding ability of IL6 and IL6R. Ingenuity Pathway Analysis (IPA) showed that IL6 and IL6R appeared to be implicated in several pathogenetic mechanisms associated with COVID-19 severity and mortality as well as with neurodegenerative diseases mediated by neuroinflammation. Thus, the availability of IL6-IL6R-related biomarkers for COVID-19 may be helpful to counteract harmful complications and prevent multiorgan failure. At the same time, IL6-IL6R-related biomarkers could also be useful for assessing the susceptibility and progression of neuroinflammatory disorders and undertake the most suitable treatment strategies to improve patients' prognosis and quality of life. In conclusion, this study showed how IL6 pleiotropic activity could be exploited to meet different clinical needs and realize personalized medicine protocols for chronic, age-related and modern public health emergencies.

Genetic analysis of intellectual disability and autism.

BACKGROUND AND AIM: Intellectual disability (ID) and autism spectrum disorders (ASD) are neurodevelopmental conditions that often co-exist and affect children from birth, impacting on their cognition and adaptive behaviour. Social interaction and communication ability are also severely impaired in ASD. Almost 1-3% of the population is affected and it has been estimated that approximately 30% of intellectual disability and autism is caused by genetic factors. The aim of this review is to summarize monogenic conditions characterized by intellectual disability and/or autism for which the causative genes have been identified. METHODS AND RESULTS: We identified monogenic ID/ASD conditions through PubMed and other NCBI databases. Many such genes are located on the X chromosome (>150 out of 900 X-linked protein-coding genes), but at least 2000 human genes are estimated to be involved in ID/ASD. We selected 174 genes (64 X-linked and 110 autosomal) for an NGS panel in order to screen patients with ID and/or ASD, after fragile X syndrome and significant Copy Number Variants have been excluded. CONCLUSIONS: Accurate clinical and genetic diagnosis is required for precise treatment of these disorders, but due to their genetic heterogeneity, most cases remain undiagnosed. Next generation sequencing technologies have greatly enhanced the identification of new genes associated with intellectual disability and autism, ultimately leading to the development of better treatment options.

Two rare PROX1 variants in patients with lymphedema.

BACKGROUND: The PROX1 gene is specifically expressed in a subpopulation of endothelial cells that, by budding and sprouting, give rise to the lymphatic system. It also plays a critical role in neurogenesis and during development of many organs, such as the eye lens, liver, and pancreas. METHODS: We used next-generation sequencing (NGS) to sequence the DNA of a cohort of 246 Italian patients with lymphatic malformations. We first investigated 29 known disease-causing genes: 235 of 246 patients tested negative and were then retested for a group of candidate genes, including PROX1, selected from a database of mouse models. The aim of the study was to define these patients' genotypes and explore the role of the candidate gene PROX1 in lymphedema. RESULTS: Two of 235 probands were found to carry rare heterozygous missense variants in PROX1. In silico analysis of these variants-p.(Leu590His) and p.(Gly106Asp)-indicates that the overall protein structure was altered by changes in interactions between nearby residues, leading to functional protein defects. CONCLUSIONS: Our results suggest that PROX1 is a new candidate gene for predisposition to lymphedema.

Analysis of ACE2 Genetic Variability among Populations Highlights a Possible Link with COVID-19-Related Neurological Complications.

Angiotensin-converting enzyme 2 (ACE2) has been recognized as the entry receptor of the novel severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2). Structural and sequence variants in ACE2 gene may affect its expression in different tissues and determine a differential response to SARS-Cov-2 infection and the COVID-19-related phenotype. The present study investigated the genetic variability of ACE2 in terms of single nucleotide variants (SNVs), copy number variations (CNVs), and expression quantitative loci (eQTLs) in a cohort of 268 individuals representative of the general Italian population. The analysis identified five SNVs (rs35803318, rs41303171, rs774469453, rs773676270, and rs2285666) in the Italian cohort. Of them, rs35803318 and rs2285666 displayed a significant different frequency distribution in the Italian population with respect to worldwide population. The eQTLs analysis located in and targeting ACE2 revealed a high distribution of eQTL variants in different brain tissues, suggesting a possible link between ACE2 genetic variability and the neurological complications in patients with COVID-19. Further research is needed to clarify the possible relationship between ACE2 expression and the susceptibility to neurological complications in patients with COVID-19. In fact, patients at higher risk of neurological involvement may need different monitoring and treatment strategies in order to prevent severe, permanent brain injury.

Cardiomyopathies.

The most common cardiomyopathies often present to primary care physicians with similar symptoms, despite the fact that they involve a variety of phenotypes and etiologies (1). Many have signs and symptoms common in heart failure, such as reduced ejection fraction, peripheral edema, fatigue, orthopnea, exertion dyspnea, paroxysmal nocturnal dyspnea, presyncope, syncope and cardiac ischemia (1). In all cardiomyopathies, the cardiac muscle (myocardium) may be structurally and/or functionally impaired. They can be classified as hypertrophic, dilated, left-ventricular non compaction, restrictive and arrhythmogenic right ventricular cardiomyopathies.

Non-syndromic monogenic female infertility.

Infertility is a significant clinical problem. It affects 8-12% of couples worldwide, about 30% of whom are diagnosed with idiopathic infertility (infertility lacking any obvious cause). In 2010, the World Health Organization calculated that 1.9% of child-seeking women aged 20-44 years were unable to have a first live birth (primary infertility), and 10.5% of child-seeking women with a prior live birth were unable to have an additional live birth (secondary infertility). About 50% of all infertility cases are due to female reproductive defects. Several chromosome aberrations, diagnosed by karyotype analysis, have long been known to be associated with female infertility and monogenic mutations have also recently been found. Female infertility primarily involves oogenesis. The following phenotypes are associated with monogenic female infertility: premature ovarian failure, ovarian dysgenesis, oocyte maturation defects, early embryo arrest, polycystic ovary syndrome and recurrent pregnancy loss. Here we summarize the genetic causes of non-syndromic monogenic female infertility and the genes analyzed by our genetic test.

Non-syndromic monogenic male infertility.

Infertility is a widespread clinical problem affecting 8-12% of couples worldwide. Of these, about 30% are diagnosed with idiopathic infertility since no causative factor is found. Overall 40-50% of cases are due to male reproductive defects. Numerical or structural chromosome abnormalities have long been associated with male infertility. Monogenic mutations have only recently been addressed in the pathogenesis of this condition. Mutations of specific genes involved in meiosis, mitosis or spermiohistogenesis result in spermatogenic failure, leading to the following anomalies: insufficient (oligozoospermia) or no (azoospermia) sperm production, limited progressive and/or total sperm motility (asthenozoospermia), altered sperm morphology (teratozoospermia), or combinations thereof. Androgen insensitivity, causing hormonal and sexual impairment in males with normal karyotype, also affects male fertility. The genetic causes of non-syndromic monogenic of male infertility are summarized in this article and a gene panel is proposed.

Syndromic infertility.

Infertility due to genetic mutations that cause other defects, besides infertility, is defined as syndromic. Here we describe three of these disorders for which we perform genetic tests. 1) Hypopituitarism is an endocrine syndrome characterized by reduced or absent secretion of one or more anterior pituitary hormones with consequent dysfunction of the corresponding peripheral glands. Deficiencies in all the hormones is defined as pan-hypopituitarism, lack of two or more hormones is called partial hypopituitarism, whereas absence of a single hormone is defined as selective hypopituitarism. Pan-hypopituitarism is the rarest condition, whereas the other two are more frequent. Several forms exist: congenital, acquired, organic and functional. 2) The correct functioning of the hypothalamic-pituitary-gonadal axis is fundamental for sexual differentiation and development during fetal life and puberty and for normal gonad function. Alteration of the hypothalamic-pituitary system can determine a condition called hypogonadotropic hypogonadism, characterized by normal/low serum levels of the hormones FSH and LH. 3) Primary ciliary dyskinesia is frequently associated with infertility in males because it impairs sperm motility (asthenozoospermia). Primary ciliary dyskinesia is a group of genetically and phenotypically heterogeneous disorders that show morpho-structural alterations of the cilia. Adult women with primary ciliary dyskinesia can be subfertile and have an increased probability of extra-uterine pregnancies. This is due to delayed transport of the oocyte through the uterine tubes.

Genetic syndromes with localized subcutaneous fat tissue accumulation.

Syndromes with localized accumulation of subcutaneous fatty tissue belong to a group of genetically and phenotypically heterogeneous disorders. These diseases may show some common signs, such as nodular fat, symmetrical fat masses, obesity, fatigue, lymphedema and symmetrical lipomas (painful or otherwise). Other symptoms may be specific for the different clinical entities, enabling correct differential diagnosis. Disorders belonging to this spectrum are lipedema, generalized diffuse or nodular forms of Dercum disease, localized nodular Dercum disease and multiple symmetric lipomatosis. Here we summarize the genes involved in syndromes with localized accumulation of subcutaneous fat and the test we use for genetic analysis.