Bachmann–Bupp syndrome and treatment Bachmann, André S.; VanSickle, Elizabeth A.; Michael, Julianne ...
Developmental medicine and child neurology,
April 2024, Volume:
66, Issue:
4
Journal Article
Peer reviewed
Open access
Bachmann–Bupp syndrome (BABS) is a neurodevelopmental disorder characterized by developmental delay, hypotonia, and varying forms of non‐congenital alopecia. The condition is caused by 3′‐end ...mutations of the ornithine decarboxylase 1 (ODC1) gene, which produce carboxy (C)‐terminally truncated variants of ODC, a pyridoxal 5′‐phosphate‐dependent enzyme. C‐terminal truncation of ODC prevents its ubiquitin‐independent proteasomal degradation and leads to cellular accumulation of ODC enzyme that remains catalytically active. ODC is the first rate‐limiting enzyme that converts ornithine to putrescine in the polyamine pathway. Polyamines (putrescine, spermidine, spermine) are aliphatic molecules found in all forms of life and are important during embryogenesis, organogenesis, and tumorigenesis. BABS is an ultra‐rare condition with few reported cases, but it serves as a convincing example for drug repurposing therapy. α‐Difluoromethylornithine (DFMO, also known as eflornithine) is an ODC inhibitor with a strong safety profile in pediatric use for neuroblastoma and other cancers as well as West African sleeping sickness (trypanosomiasis). Patients with BABS have been treated with DFMO and have shown improvement in hair growth, muscle tone, and development.
Bachmann‐Bupp Syndrome (BABS) is a new ODC1‐linked gain‐of‐function genetic disorder that is treatable with ODC inhibitor DFMO. BABS is an ultra‐rare disorder with major symptoms that include neurodevelopmental delay, hypotonia, and varying forms of non‐congenital alopecia. BABS belongs to a newer class of polyamine pathway‐related syndromes collectively referred to as polyaminopathies.
Noonan Syndrome is caused by variants in a variety of genes found in the RAS/MAPK pathway. As more causative genes for Noonan Syndrome have been identified, more phenotype variability has been found, ...particularly congenital heart defects. Here, we report a case of dilated coronary arteries in a pediatric patient with a RIT1 variant to add to the body of literature around this rare presentation of Noonan Syndrome. CASE PRESENTATION: A 2-month-old female was admitted due to increasing coronary artery dilation and elevated inflammatory markers. Rapid whole genome sequencing was performed and a likely pathogenic RIT1 variant was detected. This gene has been associated with a rare form of Noonan Syndrome and associated heart defects. Diagnosis of the RIT1 variant also gave reassurance about the patient's cardiac findings and allowed for more timely discharge as she was discharged to home the following day. CONCLUSIONS: This case highlights the importance of the association between dilated coronary arteries and Noonan syndrome and that careful cardiac screening should be advised in patients diagnosed with Noonan syndrome. In addition, this case emphasizes the importance of involvement of other subspecialities to determine a diagnosis. Through multidisciplinary medicine, the patient was able to return home in a timely manner with a diagnosis and the reassurance that despite her dilated coronary arteries and elevated inflammatory markers there was no immediate concern to her health.
Abstract The utilization of genetics in medical care has enhanced the utility of precision medicine and hence increased the need for clinical genetic services. These services have reduced the costs ...and expanded the availability of genetic testing, but their use is limited in certain populations. This study explores the access to clinical genetic services for Michigan patients referred to a genetics clinic on the western side of the state. Factors included the travel distance (miles), wait time for appointment (days from the referral date to the date of first appointment), population demographics, and cultural characteristics. A retrospective record review of all aged patients ( n = 568) referred to a genetics clinic in 2018 demonstrated that all patients were insured (100%), of which majority were white‐non‐Hispanic (90.7%), more than half were < 10 years of age at referral (53.3%), and most of them kept their first appointment (93.5%). Our analysis showed that the wait time was associated with referral non‐compliance, p < 0.01. Adjusting for all variables, for each additional day in wait time, patients had 1% increased risk of not seeking clinical genetic services (OR = 1.01, 90% CI 1.01, 1.02). Policies to encourage genetic service utilization and improve equitable access to precision health are needed. An opportunity exists for strategies that broaden and add diverse populations to those receiving genetic services.
The immune response to COVID-19 infection is variable. How COVID-19 influences clinical outcomes in hospitalized patients needs to be understood through readily obtainable biological materials, such ...as blood. We hypothesized that a high-density analysis of host (and pathogen) blood RNA in hospitalized patients with SARS-CoV-2 would provide mechanistic insights into the heterogeneity of response amongst COVID-19 patients when combined with advanced multidimensional bioinformatics for RNA. We enrolled 36 hospitalized COVID-19 patients (11 died) and 15 controls, collecting 74 blood PAXgene RNA tubes at multiple timepoints, one early and in 23 patients after treatment with various therapies. Total RNAseq was performed at high-density, with >160 million paired-end, 150 base pair reads per sample, representing the most sequenced bases per sample for any publicly deposited blood PAXgene tube study. There are 770 genes significantly altered in the blood of COVID-19 patients associated with antiviral defense, mitotic cell cycle, type I interferon signaling, and severe viral infections. Immune genes activated include those associated with neutrophil mechanisms, secretory granules, and neutrophil extracellular traps (NETs), along with decreased gene expression in lymphocytes and clonal expansion of the acquired immune response. Therapies such as convalescent serum and dexamethasone reduced many of the blood expression signatures of COVID-19. Severely ill or deceased patients are marked by various secondary infections, unique gene patterns, dysregulated innate response, and peripheral organ damage not otherwise found in the cohort. High-density transcriptomic data offers shared gene expression signatures, providing unique insights into the immune system and individualized signatures of patients that could be used to understand the patient's clinical condition. Whole blood transcriptomics provides patient-level insights for immune activation, immune repertoire, and secondary infections that can further guide precision treatment.
We recently described a new autosomal dominant genetic disorder in a pediatric patient caused by a heterozygous
mutation in the ornithine decarboxylase 1 (
) gene. The new genetic disorder is ...characterized by global developmental delay, alopecia, overgrowth, and dysmorphic features. We hypothesized that this new mutation (c.1342 A>T) leads to a C-terminal truncation variant of the ODC protein that is resistant to normal proteasomal degradation, leading to putrescine accumulation in cells. ODC (E.C. 4.1.1.17) is a rate-limiting enzyme in the biosynthesis of polyamines (putrescine, spermidine, and spermine) that plays a crucial role during embryogenesis, organogenesis, and tumorigenesis. In this study, we show that primary dermal fibroblasts derived from a skin biopsy of a 3-year-old patient contain large amounts of ODC protein and putrescine compared with primary dermal (neonatal and adult) fibroblast control cells. Importantly, the accumulated ODC protein variant remained functionally active as we detected exceptionally high ODC enzyme activity in both primary dermal fibroblasts (12-17-fold of controls) and red blood cells (RBCs) (125-137-fold of controls), using a specific
C radioactive ODC activity assay. Exposure of primary dermal fibroblasts to ODC inhibitor α-difluoromethylornithine (DFMO) reduced the ODC activity and putrescine to levels observed in controls without adversely affecting cell morphology or inducing cell death. In conclusion, our patient and potentially other patients that carry a similar
gain-of-function mutation might benefit from treatment with DFMO, a drug with a good safety profile, to suppress the exceptionally high ODC activity and putrescine levels in the body.
Polyamine levels are intricately controlled by biosynthetic, catabolic enzymes and antizymes. The complexity suggests that minute alterations in levels lead to profound abnormalities. We described ...the therapeutic course for a rare syndrome diagnosed by whole exome sequencing caused by gain-of-function variants in the C-terminus of ornithine decarboxylase (ODC), characterized by neurological deficits and alopecia. N-acetylputrescine levels with other metabolites were measured using ultra-performance liquid chromatography paired with mass spectrometry and Z-scores established against a reference cohort of 866 children. From previous studies and metabolic profiles, eflornithine was identified as potentially beneficial with therapy initiated on FDA approval. Eflornithine normalized polyamine levels without disrupting other pathways. She demonstrated remarkable improvement in both neurological symptoms and cortical architecture. She gained fine motor skills with the capacity to feed herself and sit with support. This work highlights the strategy of repurposing drugs to treat a rare disease.
Bachmann–Bupp syndrome (OMIM #619075) is a novel autosomal dominant disorder caused by variants in the c‐terminus of the ornithine decarboxylase 1 gene, resulting in increased levels of ornithine ...decarboxylase. This case report includes two patients diagnosed with Bachmann–Bupp syndrome who were treated with difluoromethylornithine through compassionate use approval from the United States Food and Drug Administration. In both patients, treatment with difluoromethylornithine has resulted in improved dermatologic signs, including regrowth of eyebrow and scalp hair and cessation of recurrent follicular cyst development.
The ornithine decarboxylase 1 (ODC1) gene plays an important role in physiological and cell developmental processes including embryogenesis, organogenesis, and neoplastic cell growth. Here, we report ...an 32‐month‐old Caucasian female with a heterozygous de novo nonsense mutation in the ODC1 gene that leads to a premature abrogation of 14‐aa residues at the ODC protein c‐terminus. This is the first human case confirming similar symptoms observed in a transgenic ODC1 mouse model first described over 20 years ago. Phenotypic manifestations include macrosomia, macrocephaly, developmental delay, alopecia, spasticity, hypotonia, cutaneous vascular malformation, delayed visual maturation, and sensorineural hearing loss. We here describe for the first time a new pediatric disorder that is directly linked to a de novo pathogenic variant in the ODC1 gene. The ODC1 gene mutation (c.1342 A>T) was identified by whole‐exome sequencing and confirmed by Sanger sequencing. Red blood cells obtained from our patient showed elevated ODC protein and polyamine levels compared to healthy controls. Our autosomal dominant patient who carries this gain‐of‐function ODC1 mutation may benefit from treatment with α‐difluoromethylornithine, a well‐tolerated, U.S. Food and Drug Administration (FDA). FDA‐approved drug.
In the age of genomics, public understanding of complex scientific knowledge is critical. To combat reductionistic views, it is necessary to generate and organize educational material and data that ...keep pace with advances in genomics. The view that CCR5 is solely the receptor for HIV gave rise to demand to remove the gene in patients to create host HIV resistance, underestimating the broader roles and complex genetic inheritance of CCR5. A program aimed at providing research projects to undergraduates, known as CODE, has been expanded to build educational material for genes such as
in a rapid approach, exposing students and trainees to large bioinformatics databases and previous experiments for broader data to challenge commitment to biological reductionism. Our students organize expression databases, query environmental responses, assess genetic factors, generate protein models/dynamics, and profile evolutionary insights into a protein such as CCR5. The knowledgebase generated in the initiative opens the door for public educational information and tools (molecular videos, 3D printed models, and handouts), classroom materials, and strategy for future genetic ideas that can be distributed in formal, semiformal, and informal educational environments. This work highlights that many factors are missing from the reductionist view of CCR5, including the role of missense variants or expression of CCR5 with neurological phenotypes and the role of CCR5 and the delta32 variant in complex critical care patients with sepsis. When connected to genomic stories in the news, these tools offer critically needed Ethical, Legal, and Social Implication (ELSI) education to combat biological reductionism.
The year 2020 was defined by the 29,903 base pairs of RNA that codes for the SARS-CoV-2 genome. SARS-CoV-2 infects humans to cause COVID-19, spreading from patient-to-patient yet impacts patients ...very divergently.
Within this review, we address the known molecular mechanisms and supporting data for COVID-19 clinical course and pathology, clinical risk factors and molecular signatures, therapeutics of severe COVID-19, and reinfection/vaccination. Literature and published datasets were reviewed using PubMed, Google Scholar, and NCBI SRA tools. The combination of exaggerated cytokine signaling, pneumonia, NETosis, pyroptosis, thrombocytopathy, endotheliopathy, multiple organ dysfunction syndrome (MODS), and acute respiratory distress syndrome (ARDS) create a positive feedback loop of severe damage in patients with COVID-19 that impacts the entire body and may persist for months following infection. Understanding the molecular pathways of severe COVID-19 opens the door for novel therapeutic design. We summarize the current insights into pathology, risk factors, secondary infections, genetics, omics, and drugs being tested to treat severe COVID-19.
: A growing level of support suggests the need for stronger integration of biomarkers and precision medicine to guide treatment strategies of severe COVID-19, where each patient has unique outcomes and thus require guided treatment.
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