Rare Disorder Research Articles

Dementia in Rare Genetic Neurodevelopmental Disorders: A Systematic Literature Review.

Knowledge of young-onset Alzheimer disease in adults with Down syndrome has greatly improved clinical care. However, little is known about dementia in rare genetic neurodevelopmental disorders (RGNDs). In this review, a comprehensive overview is provided of reports on dementia and cognitive/adaptive trajectories in adults with RGNDs. A systematic literature review was conducted in Embase, Medline ALL, and PsycINFO on December 6, 2022. The protocol was registered in PROSPERO (CRD42021223041). Search terms for dementia, cognitive and adaptive functioning, and RGNDs were combined using generic terms and the Orphanet database. Study characteristics and descriptive data on genetic diagnosis, clinical and neuropathologic features, comorbidities, and diagnostic methods were extracted using a modified version of the Cochrane Data Extraction Template. The literature search yielded 40 publications (17 cohorts, 23 case studies) describing dementia and/or cognitive or adaptive trajectories in adults with 14 different RGNDs. Dementia was reported in 49 individuals (5 cohorts, 20 cases) with a mean age at onset of 44.4 years. Diagnostics were not disclosed for half of the reported individuals (n = 25/49, 51.0%). A total of 44 different psychodiagnostic instruments were used. MRI was the most reported additional investigation (n = 12/49, 24.5%). Comorbid disorders most frequently associated with cognitive/adaptive decline were epilepsy, psychotic disorders, and movement disorders. Currently available literature shows limited information on aging in RGNDs, with relatively many reports of young-onset dementia. Longitudinal data may provide insights into converging neurodevelopmental degenerative pathways. We provide recommendations to optimize dementia screening, diagnosis, and research.

Laparoscopic repair for a recurrent epigastric incisional hernia following xiphoidectomy: A case report

Introduction: Xiphodynia is a rare musculoskeletal disorder characterized by epigastric or anterior chest pain, for which xiphoidectomy is considered as a definitive treatment. This procedure and its complications are not well researched, particularly within Australasian populations. We describe the novel laparoscopic incisional hernia repair from a xiphoidectomy complicated by recurrent epigastric hernias. Case Report: A 49-year-old female presented with chronic epigastric pain post-xiphoidectomy for xiphoidynia. The patient previously underwent open mesh repair for an incisional epigastric hernia, complicated by infection and subsequent removal of the mesh. A vacuum-assisted closure device was then utilized, followed by delayed primary closure. However, she experienced ongoing pain, a recurrent mass, and hypertrophic scarring, confirmed by abdominal computed tomography (CT) scan. Our laparoscopic approach involved a standard supine position with three ports and preperitoneal dissection similar to transabdominal preperitoneal (TAPP) hernia repair. The defect was 5 × 8 cm in size. A simple prolene mesh (9 × 12 cm) was secured with AsorbaTack and Glubran 2, followed by peritoneal closure with a 3/0 V-Loc suture. At two months follow-up, the patient had no evidence of recurrent hernia, no ongoing pain, and satisfactory wound healing. Conclusion: Laparoscopic surgical repair using a TAPP approach is a safe alternative to open repair of an incisional recurrent epigastric hernia post-xiphoidectomy.

Managing adult-onset Still's disease in pregnancy: A case report

BACKGROUND Adult-onset Still’s disease (AOSD) is a rare systemic inflammatory disorder characterized by fever, arthritis, skin rash, and systemic symptoms. The etiology of AOSD is unknown; however, it is thought to be related to immune dysregulation. Although a rare disease, AOSD can significantly impact reproductive health, particularly during pregnancy. This case study assesses the implications of pregnancy in a patient with AOSD, as well as the potential for heredity of the disease. Neonatal hemophagocytic lympho-histiocytosis (HLH) is a rare and life-threatening disorder characterized by hyperinflammation and uncontrolled activation of immune cells, leading to multiple organ dysfunction. This case report aimed to introduce neonatal HLH from a mother with AOSD. CASE SUMMARY This case study presents a 29-year-old female with AOSD who became pregnant and gave birth to a premature infant who was diagnosed with neonatal HLH. AOSD can significantly impact pregnancy and childbirth, as it may become more severe during pregnancy, with an increased risk of fetal loss and preterm birth. The management of AOSD during pregnancy involves the use of nonsteroidal anti-inflammatory drugs and glucocorticoids, as well as immunosuppressive agents in severe cases. However, the use of immunosuppressive agents during pregnancy may be associated with potential risks to the fetus. The hereditary implications of AOSD are unclear; however, available evidence suggests that genetic factors may play a role in the disease development. CONCLUSION AOSD can have significant implications for pregnancy and childbirth, including an increased risk of fetal loss and preterm birth. Neonatal HLH, a complication of AOSD in pregnancy, requires prompt diagnosis and management. Women with AOSD who are considering pregnancy should discuss their options with their healthcare provider and develop a management plan that addresses the potential risks to both mother and fetus.

Absence of ATM leads to altered NK cell function in mice

Ataxia-telangiectasia (A-T) is a rare disorder caused by genetic defects of A-T mutated (ATM) kinase, a key regulator of stress response, and characterized by neurodegeneration, immunodeficiency, and high incidence of cancer. Here we investigated NK cells in a mouse model of A-T (Atm−/−) showing that they are strongly impaired at killing tumor cells due to a block of early signaling events. On the other hand, in Atm−/− littermates with thymic lymphoma NK cell cytotoxicity is enhanced as compared with ATM-proficient mice, possibly via tumor-produced TNF-α. Results also suggest that expansion of exhausted NKG2D+ NK cells in Atm−/− mice is driven by low-level expression of stress-inducible NKG2D ligands, whereas development of thymoma expressing the high-affinity MULT1 ligand is associated with NKG2D down-regulation on NK cells.These results expand our understanding of immunodeficiency in A-T and encourage exploring NK cell biology in A-T patients in the attempt to identify cancer predictive biomarkers and novel therapeutic targets.

Clinical and Genetic Characterization of a Cohort of Brazilian Patients With Congenital Ataxia.

Congenital ataxias are rare hereditary disorders characterized by hypotonia and developmental motor delay in the first few months of life, followed by cerebellar ataxia in early childhood. The course of the disease is predominantly nonprogressive, and many patients are incorrectly diagnosed with cerebral palsy. Despite significant advancements in next-generation sequencing in the past few decades, a specific genetic diagnosis is seldom obtained in cases of congenital ataxia. The aim of the study was to analyze the clinical, radiologic, and genetic features of a cohort of Brazilian patients with congenital ataxia. Thirty patients with a clinical diagnosis of congenital ataxia were enrolled in this study. Clinical and demographic features and neuroimaging studies were analyzed. Genetic testing (whole-exome sequencing) was also performed. A heterogeneous pattern of genetic variants was detected. Eighteen genes were involved: ALDH5A1, BRF1, CACNA1A CACNA1G, CC2D2A, CWF19L1, EXOSC3, ITPR1, KIF1A, MME, PEX10, SCN2A, SNX14, SPTBN2, STXBP1, TMEM240, THG1L, and TUBB4A. Pathogenic/likely pathogenic variants involving 11 genes (ALDH5A1, CACNA1A, EXOSC3, MME, ITPR1, KIF1A, STXBP1, SNX14, SPTBN2, TMEM240, and TUBB4A) were identified in 46.7% of patients. Variants of uncertain significance involving 8 genes were detected in 33.3% of patients. Congenital ataxias were characterized by a broad phenotype. A genetic diagnosis was more often obtained in patients with cerebellar-plus syndrome than in patients with a pure cerebellar syndrome. This study re-emphasizes the genetic heterogeneity of congenital ataxias and the absence of a clear phenotype-genotype relationship. A specific genetic diagnosis was established in 46.7% of patients. Autosomal dominant, associated with sporadic cases, was recognized as an important genetic inheritance. The results of this analysis highlight the value of whole-exome sequencing as an efficient screening tool in patients with congenital ataxia.

Whole-exome-based single nucleotide variants and copy number analysis for prenatal diagnosis of compound heterozygosity of SMPD4.

Biallelic loss-of-function variants in SMPD4 cause a rare and severe neurodevelopmental disorder. These variants have been identified in a group of children with neurodevelopmental disorders with microcephaly, arthrogryposis, and structural brain anomalies. SMPD4 encodes a sphingomyelinase that hydrolyzes sphingomyelin into ceramide at neutral pH and can thereby affect membrane lipid homeostasis. SMPD4 localizes to the membranes of the endoplasmic reticulum and nuclear envelope and interacts with nuclear pore complexes. For the efficient prenatal diagnosis of rare and undiagnosed diseases, the parallel detection of copy number variants (CNVs) and single nucleotide variants using whole-exome analysis is required. A physical examination of the parents was performed. Karyotype and whole-exome analysis were performed for the fetus and the parents. A fetus with microcephaly and arthrogryposis; biallelic null variants (c.387-1G>A; Chr2[GRCh38]: g.130142742_130202459del) were detected by whole-exome sequencing (WES). We have reported for the first time the biallelic loss-of-function mutations in SMPD4 in patients born to unrelated parents in China. WES could replace chromosomal microarray analysis and copy number variation sequencing as a more cost-effective genetic test for detecting CNVs and diagnosing highly heterogeneous conditions.

Strengthening health systems for access to gene therapy in rare genetic disorders

Strengthening health systems for access to gene therapy in rare genetic disorders

Generation of an induced pluripotent stem cell line (SJTUGHi003-A) from a patient with Sorsby fundus dystrophy carrying c.484G>A mutation in TIMP3 gene.

Sorsby fundus dystrophy (SFD) is a rare autosomal dominant disorder with macular dystrophy and severe visual loss. Mutations in TIMP3 gene has been related to SFD with mechanisms unclear. We have successfully reprogrammed the peripheral blood mononuclear cells (PBMCs) from an SFD patient carrying c.484G>A mutation in TIMP3 gene to induced pluripotent stem cells (iPSCs) and characterized their pluripotency and genetic stability. This line may serve as a useful tool to explore the role of TIMP3 in SFD pathogenesis.

DDX58 variant triggers IFN-β-induced autophagy in trabecular meshwork and influences intraocular pressure.

Singleton-Merten syndrome (SMS) is a rare immunogenetic disorder affecting multiple systems, characterized by dental dysplasia, aortic calcification, glaucoma, skeletal abnormalities, and psoriasis. Glaucoma, a key feature of both classical and atypical SMS, remains poorly understood in terms of its molecular mechanism caused by DDX58 mutation. This study presented a novel DDX58 variant (c.1649A>C [p.Asp550Ala]) in a family with childhood glaucoma. Functional analysis showed that DDX58 variant caused an increase in IFN-stimulated gene expression and high IFN-β-based type-I IFN. As the trabecular meshwork (TM) is responsible for controlling intraocular pressure (IOP), we examine the effect of IFN-β on TM cells. Our study is the first to demonstrate that IFN-β significantly reduced TM cell viability and function by activating autophagy. In addition, anterior chamber injection of IFN-β remarkably increased IOP level in mice, which can be attenuated by treatments with autophagy inhibitor chloroquine. To uncover the specific mechanism underlying IFN-β-induced autophagy in TM cells, we performed microarray analysis in IFN-β-treated and DDX58 p.Asp550Ala TM cells. It showed that RSAD2 is necessary for IFN-β-induced autophagy. Knockdown of RSAD2 by siRNA significantly decreased autophagy flux induced by IFN-β. Our findings suggest that DDX58 mutation leads to the overproduction of IFN-β, which elevates IOP by modulating autophagy through RSAD2 inTM cells.

Posterior reversible encephalopathy syndrome with functional and motor sequelae: A case report

Posterior Reversible Encephalopathy Syndrome (PRES) is a rare clinicoradiological neurological disorder, initially elucidated in 1996, Since this first description of PRES numerous case reports and case series, as well as retrospective observational studies describing the syndrome have been published. Importantly, no randomized controlled studies have been performed, We present the case of a young patient with no significant medical history who presented with neurological symptoms consistent with Posterior Reversible Encephalopathy Syndrome (PRES). Brain MRI confirmed the diagnosis of Posterior Reversible Encephalopathy Syndrome (PRES). Additionally, the etiological assessment yielded negative results. A notable aspect in our patient's case is the persistence of sequelae, characterized by dexterity and grip impairment on the right side, hindering various activities of daily living. The diagnosis of PRES is both radiological and clinical, with MRI playing a crucial role. Treatment is primarily symptomatic, sometimes requiring intensive care unit admission. Prognosis is favorable in the majority of cases, but severe complications and even death can occur. The reversibility of initial symptoms is well-documented in the literature. Long-term functional impairment outcomes following PRES have not been adequately characterized in the literature. Therefore, it is necessary to conduct follow-up screenings in more patients presenting both typical and atypical PRES syndromes. This will provide insight into whether the functional and motor sequelae of PRES are less reversible.

Adult niemann-pick disease: A case report

Adult niemann-pick disease: A case report

Unilateral Sweating: A Case Study of Localized Unilateral Hyperhidrosis

ABSTRACT Localized unilateral hyperhidrosis (LUH) is a rare disorder with intense sweating in a specific area, often without common triggers. This study details a 32-year-old man with activity-induced unilateral sweating. Comprehensive tests ruled out serious conditions. This unique case adds to the limited reports of LUH in healthy individuals.

Diagnosis of tuberous sclerosis in the prenatal period: a retrospective study of 240 cases and review of the literature.

Tuberous sclerosis complex (TSC) is a rare multisystemic disorder caused by a pathogenic variant in the TSC1 or TSC2 gene. A great phenotypic variability characterises TSC. The condition predisposes to the formation of hamartomas in various tissues, neurologic and neurodevelopmental disorders such as epilepsy, psychiatric disorders, as well as intellectual disability in 50%. TSC may be responsible for cardiac rhabdomyomas (CRs), cortical tubers, or subependymal nodules during foetal life. Detecting multiple CRs is associated with a very high risk of TSC, but the CR could be single and isolated. Few data exist to estimate the risk of TSC in these cases. We report the largest series of prenatal genetic tests for TSC with a retrospective study of 240 foetuses presenting with suggestive antenatal signs. We also provide a review of the literature to specify the probability of clinical or genetic diagnosis of TSC in case of detection of single or multiple CRs. Indeed, an early diagnosis is crucial for the counselling of the couple and their families. In this series, a definite diagnosis was assessed in 50% (41/82) of foetuses who initially presented with a single CR and 80.3% (127/158) in cases of multiple CRs. The prevalence of parental germinal mosaicism was 2.6% (3/115).

Molecular and Evolution In Silico Studies Unlock the h4-HPPD C-Terminal Tail Gating Mechanism

The enzyme 4-hydroxyphenylpyruvate dioxygenase (4-HPPD) is involved in the catabolism of the amino acid tyrosine in organisms such as bacteria, plants, and animals. It catalyzes the conversion of 4-hydroxyphenylpyruvate to a homogenisate in the presence of molecular oxygen and Fe(II) as a cofactor. This enzyme represents a key step in the biosynthesis of important compounds, and its activity deficiency leads to severe, rare autosomal recessive disorders, like tyrosinemia type III and hawkinsinuria, for which no cure is currently available. The 4-HPPD C-terminal tail plays a crucial role in the enzyme catalysis/gating mechanism, ensuring the integrity of the active site for catalysis through fine regulation of the C-terminal tail conformation. However, despite growing interest in the 4-HPPD catalytic mechanism and structure, the gating mechanism remains unclear. Furthermore, the absence of the whole 3D structure makes the bioinformatic approach the only possible study to define the enzyme structure/molecular mechanism. Here, wild-type 4-HPPD and its mutants were deeply dissected by applying a comprehensive bioinformatics/evolution study, and we showed for the first time the entire molecular mechanism and regulation of the enzyme gating process, proposing the full-length 3D structure of human 4-HPPD and two novel key residues involved in the 4-HPPD C-terminal tail conformational change.

Characterization and Engineered U1 snRNA Rescue of Splicing Variants in a Turkish Neurodevelopmental Disease Cohort

Although they are rare in the population, rare neurodevelopmental disorders (RNDDs) constitute a significant portion of all rare diseases. While advancements in sequencing technologies led to improvements in diagnosing and managing rare neurodevelopmental diseases, accurate pathogenicity classification of the identified variants is still challenging. Sequence variants altering pre-mRNA splicing make up a significant part of pathogenic variants. Despite advances in the in silico prediction tools, noncanonical splice site variants are one of the groups of variants that pose a challenge in their clinical interpretation. In this study, we analyzed the effects of seven splicing variants we had previously proposed as disease-causing and demonstrated that all but one of the seven variants had a strong or moderate effect on splicing, as assessed by a minigene assay. Next, applying U1 snRNAs engineered for different splicing variants in the corresponding genes and expressed with minigene plasmids in HeLa cells provided a partial correction in four of the studied genes to varying degrees. Findings from our study highlight the importance of in vitro minigene-based assays for the reclassification of putative splice-altering variants of uncertain significance and the therapeutic potential of modified U1 snRNAs in RNDDs.

Afamelanotide for Treatment of the Protoporphyrias: Impact on Quality of Life and Laboratory Parameters in a US Cohort

Background: Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are rare disorders of heme biosynthesis characterized by severe cutaneous phototoxicity. Afamelanotide, an α-melanocyte-stimulating hormone analogue, is the only approved treatment for protoporphyria and leads to increased light tolerance and improved quality of life (QoL). However, published experience with afamelanotide in the US is limited. Methods: Here, we report on all adults who received at least one dose of afamelanotide at the Massachusetts General Hospital Porphyria Center from 2021 to 2022. Changes in the time to phototoxic symptom onset, QoL, and laboratory parameters were assessed before and during treatment with afamelanotide. Results: A total of 29 patients with protoporphyria were included, 26 of whom (72.2%) received ≥2 afamelanotide implants. Among the patients who received ≥2 implants, the median time to symptom onset following sunlight exposure was 12.5 min (IQR, 5–20) prior to the initiation of afamelanotide and 120 min (IQR, 60–240) after treatment (p < 0.001). Improvements in QoL during afamelanotide treatment were measured using two QoL tools, with good correlation observed between these two instruments. Finally, we found no improvements in the median levels of metal-free erythrocyte protoporphyrin, plasma protoporphyrin, or liver biochemistries during versus prior to the initiation of afamelanotide treatment. Conclusions: This study highlights a dramatic clinical benefit of afamelanotide in relation to light tolerance and QoL in protoporphyria, albeit without improvement in protoporphyrin levels or measures of liver function.

Hypoparathyroidism, deafness and renal dysplasia syndrome with bilateral cataract and bicornuate uterus caused by a de novo GATA3 mutation

Hypoparathyroidism, deafness and renal dysplasia (HDR) syndrome is a rare genetic disorder caused by haploinsufficiency of the GATA3 gene. A very limited number of cases have been reported in the literature to date. Diagnosis is challenging as the phenotypic expression has wide heterogeneity due to variable penetrance of the underlying genetic mutation. Although the condition is inherited in an autosomal dominant pattern, sporadic cases do occur. This report presents a case of a 22-year-old female diagnosed with HDR syndrome, featuring bilateral cataract and bicornuate uterus. The GATA3 mutation detected in the patient was not identified in the family, suggesting it to be arising de novo. The present case report describes the rare phenotypic findings of bilateral cataract and bicornuate uterus associated with HDR, thus expanding the clinical spectrum of the syndrome.

Towards a Cure for Diamond–Blackfan Anemia: Views on Gene Therapy

Diamond–Blackfan anemia (DBA) is a rare genetic disorder affecting the bone marrow’s ability to produce red blood cells, leading to severe anemia and various physical abnormalities. Approximately 75% of DBA cases involve heterozygous mutations in ribosomal protein (RP) genes, classifying it as a ribosomopathy, with RPS19 being the most frequently mutated gene. Non-RP mutations, such as in GATA1, have also been identified. Current treatments include glucocorticosteroids, blood transfusions, and hematopoietic stem cell transplantation (HSCT), with HSCT being the only curative option, albeit with challenges like donor availability and immunological complications. Gene therapy, particularly using lentiviral vectors and CRISPR/Cas9 technology, emerges as a promising alternative. This review explores the potential of gene therapy, focusing on lentiviral vectors and CRISPR/Cas9 technology in combination with non-integrating lentiviral vectors, as a curative solution for DBA. It highlights the transformative advancements in the treatment landscape of DBA, offering hope for individuals affected by this condition.

Molecular Aspects of Cardiometabolic Diseases: From Etiopathogenesis to Potential Therapeutic Targets

Cardiometabolic diseases (CMDs) encompass a range of prevalent, often preventable, non-communicable illnesses, including myocardial infarction, stroke, cardiac insufficiency, arterial hypertension, obesity, type 2 diabetes mellitus, insulin resistance, chronic renal dysfunction, non-alcoholic fatty liver disease, and rare metabolic disorders [...]

Mechanisms and Delivery of tRNA Therapeutics.

Transfer ribonucleic acid (tRNA) therapeutics will provide personalized and mutation specific medicines to treat human genetic diseases for which no cures currently exist. The tRNAs are a family of adaptor molecules that interpret the nucleic acid sequences in our genes into the amino acid sequences of proteins that dictate cell function. Humans encode more than 600 tRNA genes. Interestingly, even healthy individuals contain some mutant tRNAs that make mistakes. Missense suppressor tRNAs insert the wrong amino acid in proteins, and nonsense suppressor tRNAs read through premature stop signals to generate full length proteins. Mutations that underlie many human diseases, including neurodegenerative diseases, cancers, and diverse rare genetic disorders, result from missense or nonsense mutations. Thus, specific tRNA variants can be strategically deployed as therapeutic agents to correct genetic defects. We review the mechanisms of tRNA therapeutic activity, the nature of the therapeutic window for nonsense and missense suppression as well as wild-type tRNA supplementation. We discuss the challenges and promises of delivering tRNAs as synthetic RNAs or as gene therapies. Together, tRNA medicines will provide novel treatments for common and rare genetic diseases in humans.