| Literature DB >> 35216282 |
Sharon Hausman-Cohen1, William LaValley2, Heather Way3, Emily Gutierrez4, Jordan Reeder1.
Abstract
Molecular biology combined with genomics can be a powerful tool for developing potential intervention strategies for improving outcomes in children with autism spectrum disorders (ASD). Monogenic etiologies rarely cause autism. Instead, ASD is more frequently due to many polygenic contributing factors interacting with each other, combined with the epigenetic effects of diet, lifestyle, and environment. One limitation of genomics has been identifying ways of responding to each identified gene variant to translate the information to something clinically useful. This paper will illustrate how understanding the function of a gene and the effects of a reported variant on a molecular level can be used to develop actionable and targeted potential interventions for a gene variant or combinations of variants. For illustrative purposes, this communication highlights a specific genomic variant, SHANK3. The steps involved in developing molecularly genomically targeted actionable interventions will be demonstrated. Cases will be shared to support the efficacy of this strategy and to show how clinicians utilized these targeted interventions to improve ASD-related symptoms significantly. The presented approach demonstrates the utility of genomics as a part of clinical decision-making.Entities:
Keywords: PDD (pervasive developmental disorder); PMS (Phelan-McDermid syndrome); SHANK3 (SH3 and multiple ankyrin repeat domains 3); SNP (small nucleic polymorphism); autism spectrum disorder (ASD); clinical decision support tool (CDS tool); genomics; glutamate; molecular biology; personalized medicine; variant
Mesh:
Substances:
Year: 2022 PMID: 35216282 PMCID: PMC8879068 DOI: 10.3390/ijms23042167
Source DB: PubMed Journal: Int J Mol Sci ISSN: 1422-0067 Impact factor: 5.923
Figure 1Overview of the approach used, from identification of a gene variant to presentation with potential interventions in the CDS.
Figure 2(A) In the presence of lower intracellular zinc levels, SHANK3 is inactive and can form oligomers (black SHANK3 on the left). With low zinc, there is lower recruitment and maturation of AMPA receptors. (B) Increased intracellular zinc levels allow SHANK3 to take an active conformation, forming a scaffolding protein and promoting the recruitment and maturation of synaptic AMPA glutamatergic receptors, thus increasing glutamatergic signaling pathways.
Summary of the patient’s reported clinical symptoms and treatment regimen before ordering genomic CDS. The symptoms and therapeutic regimen are noted below.
| Primary Symptoms Reported | Treatments, Prior to Genomic Testing |
|---|---|
|
Aggression/Rage Delayed speech Difficulty with switching tasks Inflexibility Introverted Overweight Picky eater Poor social skills Difficulties with emotional engagement |
CBD/THC 3:1 ratio, as needed Methylphenidate, 4 mg daily High olive oil diet Prebiotic inulin Sertraline, 150 mg daily After nutritional studies came back, the following were added Omega-3s B vitamins NAC Vitamin D |
Summary of the treatments prescribed after genomic testing and the improved outcomes after six weeks on these treatments. Bid = bi-daily; * = some improvement; ** = notable improvement.
| Treatments, Post-Genetic Testing | Outcomes of Personalized Treatment, after 6 Weeks |
|---|---|
|
N-Acetylcysteine Continue dairy-free gluten-free diet Melatonin, 1mg at night Vitamin D3 Increasing dietary fiber Omega-3s Methylfolate, vitamin B6, and vitamin B12 combination supplement Zinc, 45 mg bid Sulforaphane with myrosinase Liposomal glutathione Oxytocin Sertraline, 100mg twice daily Palmitoylethanolamide Specialized proresolving mediators (resolvins) Ibuprofen, as needed Amantadine |
Grudge-holding resolved * Aggression/rage resolved much easier ** Lower obsessive-compulsive symptoms * Healthier gut ** Tolerant of new dietary changes ** Healthy weight loss ** Significant improvements in verbal communication * |
A sampling of genetic variants that were found in the patients described above. Superscripts next to the gene symbol represent the presence of the variant in the corresponding patient’s case (1 = Patient 1, 2 = Patient 2, etc.).
| Gene and Variant | Gene Function | Variant Effect |
|---|---|---|
| TNFa 2,5,6; | TNFa is a pro-inflammatory cytokine that helps regulate the cytokine cascade of inflammation. | This variant results in increased transcription and production of TNFa. This SNP is in the major histocompatibility complex and has been associated with autoimmune diseases such as celiac disease [ |
| IL1B 1,2,3,4,5,6; | IL1B is a pro-inflammatory cytokine involved in early development. Additionally, IL1B stimulates other pro-inflammatory cytokines, such as IL6, and can cross the blood-brain barrier, which can result in alterations of neuroendocrine function. | This variant results in increased IL1B, which can lead to neuroinflammation. This inflammation in the brain has been associated with decreased neurogenesis and increased stress, anxiety, and social interactions [ |
| OXTR 1,3,5,6; | OXTR is the receptor for the hormone, oxytocin. Oxytocin is involved in regulating social behavior and bonding, as well as playing a role in reproduction and childbirth. | This variant, located in the promoter region, is suggested to alter oxytocin signaling. Lower oxytocin signaling has been associated with decreased pair-bonding and social skill scores. This variant has also been associated with impaired social cognition, as can be seen in ASD [ |
| TCN1 1,2,5; | TCN1 is a vitamin B12 binding protein that aids in the protection of B12 from digestive acids in the stomach and promotes its cellular uptake via receptor-mediated endocytosis. | This variant is suggested to increase TCN1 expression, which is associated with lower vitamin B12 levels. This is due to TCN1 carrying 80–90% of serum B12, with the rest being carried by TCN2 to the brain and other organs. Upregulation of TCN1 lowers the B12 available for TCN2 [ |
| GCLC 1,2,3; | GCLC is the first rate-limiting step to produce glutathione. This enzyme catalyzes the reaction that combines glutamate and cysteine to produce gamma-glutamyl-cysteine. | While the full scope of this variant’s effects is not currently elucidated, it is associated with decreased glutathione synthesis. Therefore, it is likely a mechanism in which the enzymatic activity of GCLC is affected [ |
| GSTP1 5; | GSTP1 encodes one of the glutathione transferase enzymes. This enzyme is involved in the attachment of toxins, carcinogens, and drugs to a reduced glutathione molecule. | This variant is associated with lower enzymatic activity, specificity for substrate, and thermal stability. This decreases the ability to conjugate reduced glutathione with toxins for removal [ |
| HLA-DQ2.5 6; | HLA plays an important role in antigen presentation to CD4+ T cells. HLA-DQ2.5 presents gluten peptides to these immune cells. | The HLA-DQ2.5 variant has a conformation that leads to an increased immunological response to the presentation of gluten peptides. This is associated with an increased risk of developing celiac disease [ |
| PEMT 1,2,3,4,5; | PEMT is necessary for the conversion of phosphatidylethanolamine to phosphatidylcholine, which is the precursor to choline. Choline is needed to make acetylcholine and phospholipid membranes through its activity as a methyl donor. | This variant is associated with decreased enzymatic activity, lower phosphatidylcholine synthesis and, therefore, lower choline levels. Alterations in choline levels have been demonstrated in individuals with ASD, as well as downstream effects on methylation pathways, due to PEMT’s role as a methyl donor [ |