An Unusual Presentation of Succinic Semialdehyde Dehydrogenase Deficiency: A Fatal Case of Severe Progressive Seizures in a Four-Month-Old Infant

Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare genetic condition with approximately 450 patients reported worldwide, inherited in an autosomal recessive manner affecting gamma-aminobutyric acid (GABA) metabolism, characterized by varied clinical features. We report a fetal case of a four-month-old female infant presenting with severe, progressive seizures leading to fatality. Despite aggressive medical interventions, including multiple antiepileptic medications and a ketogenic diet, the patient's condition deteriorated rapidly. Genetic testing revealed a homozygous mutation in the aldehyde dehydrogenase 5 family member A1 (ALDH5A1) gene. This present case emphasizes the difficulties in controlling SSADH deficiency and emphasizes the necessity for additional studies on successful therapy approaches.

Practical Tips on Epidermolysis Bullosa for Caregivers: Part 2

The heritable condition epidermolysis bullosa (EB) is a rare but potentially devastating and life-threatening condition that is characterized primarily by cutaneous fragility, manifested when the dermis and epidermis fail to adhere properly. EB has no cure, and because of its rarity, few healthcare professionals have experience in treating it. Most families with an EB child are forced to rely on family caregiving which can be disruptive to family routines but, more importantly, place enormous time and emotional and financial burdens on the family. EB can be extremely painful, and families are often caught in the bind of trying to manage overwhelming financial burdens in an effort to help their children cope with excruciating pain. For many years, the nonprofit organization NoBabyBlisters.org has worked on five continents with families caring for EB children. Many of these families reside in under-developed nations with hot climates and limited healthcare resources. Over time, the healthcare professionals with NoBabyBlisters.org have worked with EB families both internationally and in the United States to develop a series of simple tips or "hacks" that may provide relief or great benefit to these children. The objective of this article is to share these field-tested tips with a wider audience. This is not a scientific study or a systematic review and is offered as a companion article to an earlier article on the same subject.

Familial Deep Vein Thrombosis in a Child With Antithrombin III Deficiency: A Case Report

Deep vein thrombosis (DVT) is caused by a clot (thrombus) formed in the deep veins, usually the legs. The incidence of DVT is notably less prevalent in children than in adults. Here, we present a rare case of DVT in an eight-year-old female child with a significant family history involving the untimely death of the maternal aunt. The child presented with pain and edema in the left lower limb causing immobilization without any obvious cause. The clinical features suggested the possibility of DVT. On further evaluation and radiological investigations, the diagnosis of DVT was confirmed. A complete thrombophilia workup was done showing antithrombin (AT) III deficiency. The patient was then started on low-molecular-weight heparin, leading to improvement in the symptoms. Oral rivaroxaban was continued for the patient on discharge.

A Cross-Sectional Study of Quality of Life in Patients Enrolled in the Romanian Hereditary Angioedema Registry

BACKGROUND

Hereditary angioedema (HAE) is a rare potentially life-threatening genetic disorder characterized by recurrent episodes of angioedema without wheals that can affect any part of the body. The unpredictability of the attacks and the risk of passing the disease to the offspring result in significant physical and emotional burdens for patients, with a negative impact on quality of life. Data about the health-related quality of life in HAE patients from Romania are scarce. This study aimed to evaluate the disease-specific quality of life in patients with HAE from Romania and to determine associated factors.

METHODS

The study included adult patients with HAE enrolled in the Romanian HAE Registry. Disease-specific quality of life was measured using the Hereditary Angioedema Quality of Life questionnaire, a cross-culturally adapted, internationally validated structured survey.

RESULTS

The survey was completed by 94 patients (64.9% females; 35.1% males). The mean age of the participants was 44.9 years (SD 14.1). Most patients (88.3%) had type I HAE and were from urban areas (63.8%). The mean ages at symptom onset and diagnosis were 15.1 (SD 11.1) and 36.1 (SD 14.1) years, respectively. The mean diagnosis delay was 20.5 years (SD 14.2). In the evaluated period, all patients had at least one vial of on-demand treatment at home, and 10 were on long-term prophylaxis treatment. The general and dimensional quality of life scores were slightly above the median values of the reference scales. While the general score was not associated with sex or residence, a statistically significant, negative, weak correlation was detected with diagnostic delay.

CONCLUSION

The results suggest that despite the availability of on-demand treatment for all patients, there is a need for other diagnostic and therapeutic interventions to improve the management of the disease and the quality of life for HAE patients from Romania.

A 29-Year-Old Patient With Patau Syndrome: A Case Report on Medical Management

Patau syndrome (trisomy 13) is a chromosomal abnormality with multiple malformations due to an additional copy of chromosome 13. This genetic condition has a systemic impact on the development of the human body, which can result in, but is not limited to, microphthalmia, microcephaly, low-set ears, cleft palate, cardiac abnormalities, and abdominal wall defects. It is associated with severe physical and intellectual disabilities and a limited lifespan. Here, we present a 29-year-old female with a high suspicion of the mosaic form of Patau syndrome. She decided to opt for an elective robotic-assisted vaginal hysterectomy (RAVH) due to worsening menorrhagia and recurrent miscarriages. In addition, the importance of medical interventions from surgery to anesthesia is discussed, with their role in improving the quality of life of the patient.

Multidisciplinary and multidimensional approaches to transplantation in children with rare genetic kidney diseases

In this review, we describe the multidisciplinary, multidimensional care required to optimize outcomes for pediatric transplant recipients with rare genetic kidney diseases. Transplant success, recipient survival, and improvement in quality of life depend on collaboration between patients, families, and a team of specialists with medical, as well as nonmedical expertise. A multidisciplinary transplant team composed of experts from medicine, surgery, nursing, nutrition, social services, transplant coordination, psychology, and pharmacology, is now standard in most transplant centers and is critical to the success of a transplant. In addition to these professionals, other specialists, such as cardiologists, urologists, geneticists, metabolic disease specialists, occupational therapists, case management, child life, chaplain, and palliative care services, have a crucial role to play in the preparation, surgery, and follow-up care, especially when a pediatric patient has a rare genetic disorder leading to renal involvement, and the need for transplantation. In order to describe this multidisciplinary care, we divide the genetic renal diseases into five subgroups-metabolic and tubular disorders, glomerular diseases, congenital anomalies of the kidney and urinary tract, ciliopathies including cystic diseases, and miscellaneous renal conditions; and describe for each, the need for care beyond that provided by the standard transplant team members.

An Infant With Primrose Syndrome: A Case Report

Primrose syndrome is a rare autosomal dominant disorder that is characterized by recognizable facial phenotype, sensorineural hearing loss, hypotonia, and developmental delay. All reported probands show de novo ZBTB20 pathogenic variant. Since its discovery in 1982, Primrose syndrome has remained an underdiagnosed condition. Awareness of presentation and prompt diagnostic workup are crucial for early identification and proper management. In this case report, we discuss a case of Primrose syndrome diagnosed in an infant born at Wellspan Hospital in York, PA. The patient exhibited classic phenotypic features, including a high hairline, high-arched palate, and brachycephaly at birth, as well as an absent corpus callosum observed on postnatal MRI and genotypic findings of a pathogenic variant in ZBTB20.

Uncommonly Missed Diagnosis of Methylmalonic Acidemia (MMA) in Adults and Usefulness of Testing for MMA in Cases of Seizures/Neuropathy/Weakness/Ataxia

Methylmalonic acidemia (MMA) is a genetic condition affecting cobalamin metabolism causing elevated serum and urine methylmalonic acid without B12 deficiency. MMA presents with ketoacidotic hyperammonemic coma in newborns and can result in neonatal death or severe neurological disability. Rarely, this diagnosis is missed, or patients do not present until later in life. Presentation of this life-threatening condition is variable in adults. Improvement is rapid with IV cobalamin and a specialized diet. This case is intended to increase clinician's awareness of the late presentation of this disease and the importance of high clinical suspicion and prompt diagnosis. We present a case of a 32-year-old man with seizures, polyneuropathy, ataxia, and memory loss which were unexplained until diagnosis with MMA. We aim to help clinicians understand the variable presentation and diagnostic work-up of MMA to prevent catastrophic missed diagnoses. After an extensive work-up, the patient was found to have methylmalonic acidemia and was promptly treated with high dose vitamin B12 and a specialized diet with low protein including restricted isoleucine, threonine, methionine, and valines as well as a high caloric content. The patient showed significant clinical improvement with this treatment. To our knowledge, this is the first case of MMA presenting with these symptoms in a medically stable adult. The patient was adopted from abroad and therefore, lacked access to normal newborn screenings, further complicating diagnosis. We aim to demonstrate to clinicians the importance of considering this diagnosis in patients in whom symptoms may be suggestive, particularly if they lack access to genetic or metabolic screening.

The Impact of Artificial Intelligence on Optimizing Diagnosis and Treatment Plans for Rare Genetic Disorders

Rare genetic disorders (RDs), characterized by their low prevalence and diagnostic complexities, present significant challenges to healthcare systems. This article explores the transformative impact of artificial intelligence (AI) and machine learning (ML) in addressing these challenges. It emphasizes the need for accurate and early diagnosis of RDs, often hindered by genetic and clinical heterogeneity. This article discusses how AI and ML are reshaping healthcare, providing examples of their effectiveness in disease diagnosis, prognosis, image analysis, and drug repurposing. It highlights AI's ability to efficiently analyze extensive datasets and expedite diagnosis, showcasing case studies like Face2Gene. Furthermore, the article explores how AI tailors treatment plans for RDs, leveraging ML and deep learning (DL) to create personalized therapeutic regimens. It emphasizes AI's role in drug discovery, including the identification of potential candidates for rare disease treatments. Challenges and limitations related to AI in healthcare, including ethical, legal, technical, and human aspects, are addressed. This article underscores the importance of data ethics, privacy, and algorithmic fairness, as well as the need for standardized evaluation techniques and transparency in AI research. It highlights second-generation AI systems that prioritize patient-centric care, efficient patient recruitment for clinical trials, and the significance of high-quality data. The integration of AI with telemedicine, the growth of health databases, and the potential for personalized therapeutic recommendations are identified as promising directions for the field. In summary, this article provides a comprehensive exploration of how AI and ML are revolutionizing the diagnosis and treatment of RDs, addressing challenges while considering ethical implications in this rapidly evolving healthcare landscape.

Clinical Disease States Related to Mutations of the NOD2 Gene: A Case Report and Literature Review

Nucleotide-binding oligomerization domain-containing protein 2 (NOD2) is a protein encoded by the NOD2 gene and plays an important role in the immune system. NOD2 is an intracellular pattern recognition receptor (PRR) responsible for the recognition of pathogens as well as the activation of many biochemical processes within cells of the host immune system. Mutations of the NOD2 gene can significantly impact the host's immune response against a variety of pathogens. In addition to immunodeficiency, mutations of the NOD2 gene have also been linked with several atopic diseases and autoimmune conditions such as rheumatoid arthritis and Crohn's disease (CD). There is also a distinct set of autoinflammatory conditions that are now classified as NOD2-associated autoinflammatory diseases (NAID). We present a case of a 63-year-old female with common variable immunodeficiency, eosinophilic asthma, and rheumatoid arthritis who was found to have a NOD2 mutation on genetic testing. As genetic testing continues to gain popularity, several disease states that were previously thought to be unrelated are now being recognized as originating from a common genetic defect.

PTRH2 Gene Variants: Recent Review of the Phenotypic Features and Their Bioinformatics Analysis

Peptidyl-tRNA hydrolase 2 (PTRH2) is an evolutionarily highly conserved mitochondrial protein. The biallelic mutations in the PTRH2 gene have been suggested to cause a rare autosomal recessive disorder characterized by an infantile-onset multisystem neurologic endocrine and pancreatic disease (IMNEPD). Patients with IMNEPD present varying clinical manifestations, including global developmental delay associated with microcephaly, growth retardation, progressive ataxia, distal muscle weakness with ankle contractures, demyelinating sensorimotor neuropathy, sensorineural hearing loss, and abnormalities of thyroid, pancreas, and liver. In the current study, we conducted an extensive literature review with an emphasis on the variable clinical spectrum and genotypes in patients. Additionally, we reported on a new case with a previously documented mutation. A bioinformatics analysis of the various PTRH2 gene variants was also carried out from a structural perspective. It appears that the most common clinical characteristics among all patients include motor delay (92%), neuropathy (90%), distal weakness (86.4%), intellectual disability (84%), hearing impairment (80%), ataxia (79%), and deformity of head and face (~70%). The less common characteristics include hand deformity (64%), cerebellar atrophy/hypoplasia (47%), and pancreatic abnormality (35%), while the least common appear to be diabetes mellitus (~30%), liver abnormality (~22%), and hypothyroidism (16%). Three missense mutations were revealed in the PTRH2 gene, the most common one being Q85P, which was shared by four different Arab communities and was presented in our new case. Moreover, four different nonsense mutations in the PTRH2 gene were detected. It may be concluded that disease severity depends on the PTRH2 gene variant, as most of the clinical features are manifested by nonsense mutations, while only the common features are presented by missense mutations. A bioinformatics analysis of the various PTRH2 gene variants also suggested the mutations to be deleterious, as they seem to disrupt the structural confirmation of the enzyme, leading to loss of stability and functionality.

Pathogenic Presentation of a Variant of Uncertain Significance in a Puerto Rican Patient With Wiedemann-Steiner Syndrome

Wiedemann-Steiner syndrome (WDSTS) is an autosomal dominant disorder that is caused by mutations in the KMT2A gene. This case reports a two-year-old male's diagnosis of WDSTS via a heterozygous variant of uncertain significance (VUS) (c.11735G>A(p.Cys3912Tyr). The patient's phenotypic presentation was remarkable for hypertrichosis, intellectual disability, intermittent aggressive behavior, developmental delay, failure to thrive, low weight, and the distinct facial features of long eyelashes, telecanthus, corrected strabismus, down-slanting palpebral fissures, and a wide nasal bridge with a broad tip. The importance of this case report stands on the principle of genetic evaluation in patients with ambiguous clinical presentations. In the future, molecular analysis of VUS with pathogenic clinical features can lead to targeted medical management and counseling.

The implementation of an enhanced clinical model to improve the diagnostic yield of exome sequencing for patients with a rare genetic disease: A Canadian experience

The introduction of clinical exome sequencing (ES) has provided a unique opportunity to decrease the diagnostic odyssey for patients living with a rare genetic disease (RGD). ES has been shown to provide a diagnosis in 29%-57% of patients with a suspected RGD, with as many as 70% remaining undiagnosed. There is a need to advance the clinical model of care by more formally integrating approaches that were previously considered research into an enhanced diagnostic workflow. We developed an Exome Clinic, which set out to evaluate a workflow for improving the diagnostic yield of ES for patients with an undiagnosed RGD. Here, we report the outcomes of 47 families who underwent clinical ES in the first year of the clinic. The diagnostic yield from clinical ES was 40% (19/47). Families who remained undiagnosed after ES had the opportunity for follow-up studies that included phenotyping and candidate variant segregation in relatives, genomic matchmaking, and ES reanalysis. This enhanced diagnostic workflow increased the diagnostic yield to 55% (26/47), predominantly through the resolution of variants and genes of uncertain significance. We advocate that this approach be integrated into mainstream clinical practice and highlight the importance of a coordinated translational approach for patients with RGD.

A Medical Conundrum in a Surgical Setting: Lessons Learned From an Atypical Case of Hyponatremia

In the world of medicine and specifically endocrinology, hyponatremia is one of the commonest electrolyte abnormalities that result in a varied spectrum of presentations. Patients can incur symptoms ranging from lethargy, light-headedness, and confusion to much more severe symptoms such as vomiting, abdominal pain, deterioration in consciousness, and, in critical cases, even seizures. In elderly patients, hyponatremia is a major cause of Delirium and if not treated appropriately, can result in adverse outcomes and complications. In severe cases of hyponatremia, the opinion of an endocrinologist must be sought early for a conscientious investigation of the underlying etiology, as this prevents the need for unnecessary interventions, and thus reduces the risk of potential harm. Despite being a common electrolyte abnormality, hyponatremia can be associated with rare and uncommon etiologies, one of them being acute intermittent porphyria (AIP) as seen in our case. Due to the non-specific presentation of AIP, medical and healthcare professionals must be cautious of this condition, since it can mimic an acute abdomen. Symptoms of AIP usually overlap with other conditions, thus resulting in a diagnostic dilemma. Triggers and factors leading to acute attacks of AIP must be explored and rationalized appropriately, involving a thorough review of a patient's medication and social history. Moreover, discussion in a multidisciplinary team (MDT) setting for such complex presentations has a positive impact on patient care and is therefore recommended.

A Case of a 23-Year-Old Male With Leber Hereditary Optic Neuropathy With a Rare Mutation

Mitochondrial DNA (mtDNA) is responsible for encoding 13 subunits of the respiratory chain. These subunits are crucial in providing reducing equivalents for the energy-intensive intracellular processes. Leber hereditary optic neuropathy (LHON) is a mitochondrial illness that causes carcinogenesis due to oxidative stress and painless loss of central vision as a result of selective degradation of retinal ganglion cells as well as their axons. We present a case of a 23-year-old male patient who was diagnosed with subacute LHON. The mutation in our patient was found in a less commonly mutated exon sequence of MT-NDL4, which codes for NADH (nicotinamide adenine dinucleotide hydrogen, reduced) dehydrogenase subunit 4L. The MT-ND4L exon is located immediately upstream of the MTD4 exon on the human mtDNA. The take-home message is to always perform a comprehensive mitochondrial genome analysis for identifying rare mutations when LHON is suspected.

Health-Related Quality of Life of Patients with Marfan Syndrome-Polish Study

Background: Despite extensive knowledge about the quality of life of people suffering from rare diseases, data on patients with Marfan syndrome (MFS) are scarce and inconsistent. Hence, the problem of assessing the quality of life (QOL) and its relationship with the assessment of which ailments are the most burdensome for these patients is still open. Aim: Comparison of the quality of life of patients with MFS and determination as to which of the reported complaints in patients with MFS are related to the QOL of patients. Methods: The study included 35 patients with MFS and 35 healthy controls, matched for gender and age. In the study, the questionnaire of quality of life assessment SF-36 was used to assess the level of health-related quality of life, as well as an interview of the most severe symptoms reported by patients with MFS. Results: The level of the physical dimension of the QOL (p < 0.001) and limiting of roles due to physical health (p = 0.002), as well as the level of general index of the QOL (p < 0.001), were statistically significantly lower in MFS patients when compared to controls. People from both studied groups do not vary in the scope of pain, vitality, social functioning, limiting the roles due to emotional problems, and state of mind but also in the mental dimension of the health-related quality of life (HRQL). Additionally, there has been a correlation between HRQL and the subjective assessment of the effects of orthopedic, ophthalmic, and cardiological problems in life, as well as lower exercise tolerance in the evaluation of people with MFS and QOL in most areas. Conclusions: Patients with MFS present a reduced QOL in the areas of physical functioning, limiting roles due to physical health, general feeling of general health, the physical dimension of the HRQL, and the general index of the QOL; in these areas, they require careful evaluation, as well as medical and psychosocial assistance.

Thrombocytopenia With Absent Radii Syndrome With an Unusual Urological Pathology: A Case Report

Thrombocytopenia with absent radii (TAR) syndrome is a rare congenital syndrome that follows an autosomal recessive pattern of inheritance. TAR syndrome is characterized by thrombocytopenia and bilateral absence (aplasia) of the radii of the forearms. This syndrome can be associated with defects within the skeletal, cardiac, renal, or gastrointestinal systems. It is important for clinicians treating patients with TAR syndrome to be aware of the myriad of complications that may arise in the other organ systems in order to promptly diagnose and treat any associated anomalies. We present a case of an African American infant diagnosed with TAR syndrome who was also found to have grade 5 vesicoureteral reflux and moderate right hydronephrosis, as well as cow’s milk protein allergy.

Drosophila functional screening of de novo variants in autism uncovers damaging variants and facilitates discovery of rare neurodevelopmental diseases

Individuals with autism spectrum disorder (ASD) exhibit an increased burden of de novo mutations (DNMs) in a broadening range of genes. While these studies have implicated hundreds of genes in ASD pathogenesis, which DNMs cause functional consequences in vivo remains unclear. We functionally test the effects of ASD missense DNMs using Drosophila through "humanization" rescue and overexpression-based strategies. We examine 79 ASD variants in 74 genes identified in the Simons Simplex Collection and find 38% of them to cause functional alterations. Moreover, we identify GLRA2 as the cause of a spectrum of neurodevelopmental phenotypes beyond ASD in 13 previously undiagnosed subjects. Functional characterization of variants in ASD candidate genes points to conserved neurobiological mechanisms and facilitates gene discovery for rare neurodevelopmental diseases.

Future of genetic therapies for rare genetic diseases: what to expect for the next 15 years?

Introduction

Rare genetic diseases affect millions of people worldwide. Most of them are caused by defective genes that impair quality of life and can lead to premature death. As genetic therapies aim to fix or replace defective genes, they are considered the most promising treatment for rare genetic diseases. Yet, as these therapies are still under development, it is still unclear whether they will be successful in treating these diseases. This study aims to address this gap by assessing researchers' opinions on the future of genetic therapies for the treatment of rare genetic diseases.

Methods

We conducted a global cross-sectional web-based survey of researchers who recently authored peer-reviewed articles related to rare genetic diseases.

Results

We assessed the opinions of 1430 researchers with high and good knowledge about genetic therapies for the treatment of rare genetic diseases. Overall, the respondents believed that genetic therapies would be the standard of care for rare genetic diseases before 2036, leading to cures after this period. CRISPR-Cas9 was considered the most likely approach to fixing or replacing defective genes in the next 15 years. The respondents with good knowledge believed that genetic therapies would only have long-lasting effects after 2036, while those with high knowledge were divided on this issue. The respondents with good knowledge on the subject believed that non-viral vectors are more likely to be successful in fixing or replacing defective genes in the next 15 years, while most of the respondents with high knowledge believed viral vectors would be more successful.

Conclusion

Overall, the researchers who participated in this study expect that in the future genetic therapies will greatly benefit the treatment of patients with rare genetic diseases.

Deep Dive Into Familial Mediterranean Fever in a Child Without Fever

This case report entails the details of a 12-year-old Egyptian boy who had recurrent episodes of shortness of breath, ascites, and pericardial effusions starting at the age of 10, returning with worsening symptoms in April of 2020. The lab findings indicated a critically elevated C-reactive protein (CRP) of 107.2 mg/L; a clinically notable inflammation process was festering. This case was all the more interesting as this boy did not present with a fever, making the diagnosis a difficult one. Nonetheless, genetic Mediterranean fever (MEFv) and polymerase chain reaction (PCR) testing confirmed the diagnosis of familial MEFv. Steroids and colchicine-salicylate decreased the frequency of the attacks and are now on half a dose of colchicine to keep his symptoms at bay. What we see here is the risk-to-benefit ratio of the therapeutic use of colchicine in children outweighs potential side effects such as nausea, vomiting, abdominal pain, diarrhea, kidney or liver failure. However, further research is needed to access better long-term treatment plans. Another key takeaway point that can be highlighted in this case is that the patient does not need to be febrile to diagnose FMF.

Monitoring cell-mediated immune responses in AAV gene therapy clinical trials using a validated IFN-γ ELISpot method

Adeno-associated virus (AAV)-based gene therapies have recently shown promise as a novel treatment for hereditary diseases. Due to the viral origin of the vector capsid, however, cellular immune response may be elicited that could eliminate transduced target cells. To monitor cellular immune responses in clinical trials, we optimized and bioanalytically validated a sensitive, robust, and reliable interferon-γ (IFN-γ) enzyme-linked immunospot (ELISpot) assay. For method performance validation, human peripheral blood mononuclear cells (PBMCs) were stimulated with peptides derived from AAV5 capsid proteins and the encoded transgene product, human blood clotting factor VIII (FVIII), in addition to positive controls, such as peptides from the 65-kDa phosphoprotein of cytomegalovirus. We statistically assessed the limit of detection and confirmatory cutpoint, evaluated precision and linearity, and confirmed specificity using HIV peptides. Robustness parameter ranges and sample stability periods were established. The validated IFN-γ ELISpot assay was then implemented in an AAV5-FVIII gene therapy clinical trial. Cellular immune responses against the AAV5 capsid were observed in most participants as soon as 2 weeks following dose administration; only limited responses against the transgene product were detected. These data underscore the value of using validated methods for monitoring cellular immunity in AAV gene therapy trials.

Access to oral health care services for individuals with rare genetic diseases affecting skeletal development

OBJECTIVE

To identify factors associated with oral health care services for individuals with and without rare genetic diseases.

MATERIALS AND METHOD

A cross-sectional study was undertaken, with 140 individuals paired by sex and age (70 with rare genetic diseases and 70 without), aged between 3 and 27 years, and their parents. The sample was selected from two reference hospitals for patients with rare genetic diseases in southeastern Brazil. The parents completed a questionnaire on individual aspects and their child's medical/dental history. Participants who did and did not suffer from rare genetic diseases were examined for dental caries, malocclusion, dental anomalies, and oral hygiene. The theoretical model Directed Acyclic Graphs (DAG) was used to identify possible confounding variables in the association between rare diseases and access to dental care. Descriptive analyses and non-matched and matched logistic regression models (p < 0.05) were carried out.

RESULTS

The chance of individuals without rare genetic disease having access to oral health care service was 5.32 times higher (95% CI 2.35-12.01) than those with such conditions. Individuals who had not suffered upper respiratory tract infections had a 3.16 times greater chance of being in the group with access to oral health care service (95% CI 1.45-6.90).

CONCLUSION

Individuals with no rare genetic diseases and no history of upper respiratory tract infections had a greater chance of belonging to the group of individuals with access to a dental service. Individuals with rare genetic diseases have less access to oral health care.

Insulin, Insulin Everywhere: A Rare Case Report of Rabson-Mendenhall Syndrome

Rabson-Mendenhall syndrome (RMS) is a rare autosomal recessive disorder characterized by severe insulin resistance, a condition in which the body's tissues and organs do not respond appropriately to the hormone insulin. Insulin resistance impairs blood sugar regulation and ultimately leads to diabetes mellitus. A 19-year-old male presented with joint pain, blurring of vision, and generalized weakness. Investigations revealed hyperglycemia (random blood sugar (RBS) > 625 mg/dL, glycosylated hemoglobin (HbA1c) 18%), as well as sugars, protein, and ketone bodies in urine routine examination. An ultrasound of the abdomen was normal. Cardiac status was normal. Based on the clinical features, particularly the head to toe examination, skin changes, and the onset of type 2 diabetes mellitus, RMS syndrome was considered. The joint pain was alleviated with intravenous tramadol. Actrapid®, a fast-acting insulin, was given to control sugar levels, along with metformin. Vitamin B12 and pregabalin were also supplemented. A dermatological cream containing ammonium chloride, calcium lactate, glycerin, potassium chloride, sodium dihydrogen phosphate, and urea was given for skincare. It is an extremely rare disease with a frequency of fewer than one million people worldwide. Most patients survive only up to 15 years of age, although some can live into their third decade of life. Hepatic gluconeogenesis and fatty acid oxidation are affected, leading to ketoacidosis. The progression is much faster in RMS. In RMS, the genetic defect affects the insulin receptor (INSR) gene transcription with non-sense mutations and causes splicing defects. This results in premature chain termination and eventually to lower amounts of the insulin receptor messenger ribonucleic acid (mRNA). Ultimately, the number and density of insulin receptors in the plasma membrane are smaller, making the cells resistant to insulin. Herein, we report the case of a 19-year-old patient with RMS who was treated in our hospital, leading to a successful improvement in symptoms and discharge of the patient.

Clinical Application of Whole Exome Sequencing to Identify Rare but Remediable Neurologic Disorders

Background: The aim of this study was to describe the application of whole exome sequencing (WES) in the accurate genetic diagnosis and personalized treatment of extremely rare neurogenetic disorders. Methods: From 2017 to 2019, children with neurodevelopmental symptoms were evaluated using WES in the pediatric neurology clinic and medical genetics center. The clinical presentation, laboratory findings including the genetic results from WES, and diagnosis-based treatment and outcomes of the four patients are discussed. Results: A total of 376 children with neurodevelopmental symptom were evaluated by WES, and four patients (1.1%) were diagnosed with treatable neurologic disorders. Patient 1 (Pt 1) showed global muscle hypotonia, dysmorphic facial features, and multiple anomalies beginning in the perinatal period. Pt 1 was diagnosed with congenital myasthenic syndrome 22 of PREPL deficiency. Pt 2 presented with hypotonia and developmental arrest and was diagnosed with autosomal recessive dopa-responsive dystonia due to TH deficiency. Pt 3, who suffered from intractable epilepsy and progressive cognitive decline, was diagnosed with epileptic encephalopathy 47 with a heterozygous FGF12 mutation. Pt 4 presented with motor delay and episodic ataxia and was diagnosed with episodic ataxia type II (heterozygous CACNA1A mutation). The patients’ major neurologic symptoms were remarkably relieved with pyridostigmine (Pt 1), levodopa (Pt 2), sodium channel blocker (Pt 3), and acetazolamide (Pt 4), and most patients regained developmental milestones in the follow-up period (0.4 to 3 years). Conclusions: The early application of WES helps in the identification of extremely rare genetic diseases, for which effective treatment modalities exist. Ultimately, WES resulted in optimal clinical outcomes of affected patients.

The Canadian Rare Diseases Models and Mechanisms (RDMM) Network: Connecting Understudied Genes to Model Organisms

Advances in genomics have transformed our ability to identify the genetic causes of rare diseases (RDs), yet we have a limited understanding of the mechanistic roles of most genes in health and disease. When a novel RD gene is first discovered, there is minimal insight into its biological function, the pathogenic mechanisms of disease-causing variants, and how therapy might be approached. To address this gap, the Canadian Rare Diseases Models and Mechanisms (RDMM) Network was established to connect clinicians discovering new disease genes with Canadian scientists able to study equivalent genes and pathways in model organisms (MOs). The Network is built around a registry of more than 500 Canadian MO scientists, representing expertise for over 7,500 human genes. RDMM uses a committee process to identify and evaluate clinician-MO scientist collaborations and approve 25,000 Canadian dollars in catalyst funding. To date, we have made 85 clinician-MO scientist connections and funded 105 projects. These collaborations help confirm variant pathogenicity and unravel the molecular mechanisms of RD, and also test novel therapies and lead to long-term collaborations. To expand the impact and reach of this model, we made the RDMM Registry open-source, portable, and customizable, and we freely share our committee structures and processes. We are currently working with emerging networks in Europe, Australia, and Japan to link international RDMM networks and registries and enable matches across borders. We will continue to create meaningful collaborations, generate knowledge, and advance RD research locally and globally for the benefit of patients and families living with RD.

Hypomorphic Mutations in TONSL Cause SPONASTRIME Dysplasia

SPONASTRIME dysplasia is a rare, recessive skeletal dysplasia characterized by short stature, facial dysmorphism, and aberrant radiographic findings of the spine and long bone metaphysis. No causative genetic alterations for SPONASTRIME dysplasia have yet been determined. Using whole-exome sequencing (WES), we identified bi-allelic TONSL mutations in 10 of 13 individuals with SPONASTRIME dysplasia. TONSL is a multi-domain scaffold protein that interacts with DNA replication and repair factors and which plays critical roles in resistance to replication stress and the maintenance of genome integrity. We show here that cellular defects in dermal fibroblasts from affected individuals are complemented by the expression of wild-type TONSL. In addition, in vitro cell-based assays and in silico analyses of TONSL structure support the pathogenicity of those TONSL variants. Intriguingly, a knock-in (KI) Tonsl mouse model leads to embryonic lethality, implying the physiological importance of TONSL. Overall, these findings indicate that genetic variants resulting in reduced function of TONSL cause SPONASTRIME dysplasia and highlight the importance of TONSL in embryonic development and postnatal growth.

Gentamicin B1 is a minor gentamicin component with major nonsense mutation suppression activity

Nonsense mutations underlie about 10% of rare genetic disease cases. They introduce a premature termination codon (PTC) and prevent the formation of full-length protein. Pharmaceutical gentamicin, a mixture of several related aminoglycosides, is a frequently used antibiotic in humans that can induce PTC readthrough and suppress nonsense mutations at high concentrations. However, testing of gentamicin in clinical trials has shown that safe doses of this drug produce weak and variable readthrough activity that is insufficient for use as therapy. In this study we show that the major components of pharmaceutical gentamicin lack PTC readthrough activity but the minor component gentamicin B1 (B1) is a potent readthrough inducer. Molecular dynamics simulations reveal the importance of ring I of B1 in establishing a ribosome configuration that permits pairing of a near-cognate complex at a PTC. B1 induced readthrough at all three nonsense codons in cultured cancer cells with TP53 (tumor protein p53) mutations, in cells from patients with nonsense mutations in the TPP1 (tripeptidyl peptidase 1), DMD (dystrophin), SMARCAL1 (SWI/SNF-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a-like 1), and COL7A1 (collagen type VII alpha 1 chain) genes, and in an in vivo tumor xenograft model. The B1 content of pharmaceutical gentamicin is highly variable and major gentamicins suppress the PTC readthrough activity of B1. Purified B1 provides a consistent and effective source of PTC readthrough activity to study the potential of nonsense suppression for treatment of rare genetic disorders.

[Consanguineous marriage and morbi-mortality, short literature review based on an exceptional association: Usher syndrome and Von Recklinghausen neurofibromatosis]

Usher syndrome is defined by the association of a progressive or non-progressive congenital sensorineural hearing loss with variable severity and a gradually blinding pigmentary retinopathy. Von Recklinghausen neurofibromatosis or Neurofibromatosis type 1 is the major clinically form of neurofibromatosis which occurs in approximately 90% of cases. Both types of disease are genetic in origin with very low prevalence. The probability of co-occurrence of these diseases in a single individual is exceptional. Inbreeding, as well as all genetic diseases, increases quite significantly the probability of their occurrence. Consanguineous marriages are still widespread in Maghreb and in some regions of the western African. This observation reports an exceptional case of this association in a 40-year-old man of Mauritanian origin born from a consanguineous union.