Rare disease
Medical condition
TRPM3-related neurodevelopmental disorder Specialty Neurology
TRPM3-related neurodevelopmental disorder [ 1] is a monogenetic developmental and epileptic encephalopathy that affects the central nervous system .[ 2] The broad phenotype includes global developmental delay , intellectual disability , epilepsy , musculoskeletal anomalies, altered pain perception, ataxia , hypotonia , nystagmus , and cerebellar atrophy.[ 2] [ 3] [ 4]
The earliest sign for TRPM3-related neurodevelopmental disorder is usually congenital hypotonia . Infant feeding issues including dysphagia and gastroesophageal reflux are also reported.[ 1] Global developmental delay is nearly always present along with mild-to-severe intellectual disability .[ 1] [ 2] [ 4] Epilepsy is reported in 50% of cases.[ 1] [ 2]
Other signs of TRPM3-related neurodevelopmental disorder are dysmorphic facial features, scoliosis , hip dysplasia , exotropia , strabismus , nystagmus , ataxia , and altered pain perception.[ 1] [ 2]
TRPM3-related neurodevelopmental disorder is an autosomal dominant genetic disorder .[ 1] It is caused by missense mutations in the TRPM3 gene.[ 1] [ 2] Since the general population has numerous truncating variants and microdeletions throughout TRPM3 , the underlying mechanism for neurodevelopmental disorder is not haploinsufficiency .[ 3]
Research has shown that the disease-associated mutations lead to a gain-of-function . The mutations produce increased basal activity of the TRPM3 ion channel as well as increased response to chemical and noxious heat stimuli. The gain-of-function results in increased intracellular Ca2+ . It is possible that this increased channel activity and/or Ca2+ induced nerve damage could be the underlying mechanism of the disease.[ 5] [ 6] [ 2]
Diagnosis is made through genetic testing using an intellectual disability or epilepsy multigene panel that includes TRPM3 or whole exome sequencing .[ 1] Following identification of a mutation in the TRPM3 gene, alterations in channel activity are evaluated using electrophysiological assays and calcium imaging[ 2] [ 6] [ 5]
There is currently no known cure or treatment for TRPM3-related neurodevelopmental disorder. Treatment for individual manifestations of symptoms may follow standard of care (anti-epileptic medication for seizures , physical therapy , occupational therapy , speech therapy , etc).[ 1]
A single study points to the anti-convulsant drug primidone as an off label therapeutic.[ 7] Primidone is a known TRPM3 antagonist.[ 8]
Life span is apparently not impacted by TRPM3-related neurodevelopmental disorder. Not enough data currently exists to understand the disease progression.[ 1]
There are currently >30 reported cases of TRPM3-related neurodevelopmental disorder.[ 1] [ 4] [ 2] [ 9] [ 10] [ 11] It is unknown what the prevalence of this disorder is worldwide.
TRPM3 Foundation
^ a b c d e f g h i j k Dyment, David; Lines, Matthew; Innes, A Micheil (2023-02-23). "TRPM3-Related Neurodevelopmental Disorder" . University of Washington, Seattle. PMID 36821706 .
^ a b c d e f g h i Burglen, Lydie; Van Hoeymissen, Evelien; Qebibo, Leila; et al. (2023). "Gain-of-function variants in the ion channel gene TRPM3 underlie a spectrum of neurodevelopmental disorders" . eLife . 12 . doi :10.7554/elife.81032 . PMC 9886277 . PMID 36648066 .
^ a b Dyment, David A.; Terhal, Paulien A.; Rustad, Cecilie F.; et al. (2019). "De novo substitutions of TRPM3 cause intellectual disability and epilepsy" . European Journal of Human Genetics . 27 (10): 1611– 1618. doi :10.1038/s41431-019-0462-x . PMC 6777445 . PMID 31278393 . S2CID 195804345 .
^ a b c Lines, Matthew A.; Goldenberg, Paula; Wong, Ashley; et al. (2022). "Phenotypic spectrum of the recurrent TRPM3 p.( Val837Met ) substitution in seven individuals with global developmental delay and hypotonia" . American Journal of Medical Genetics Part A . 188 (6): 1667– 1675. doi :10.1002/ajmg.a.62673 . PMID 35146895 . S2CID 246749002 .
^ a b Zhao, Siyuan; Yudin, Yevgen; Rohacs, Tibor (2020). "Disease-associated mutations in the human TRPM3 render the channel overactive via two distinct mechanisms" . eLife . 9 . doi :10.7554/elife.55634 . PMC 7255801 . PMID 32343227 .
^ a b Van Hoeymissen, Evelien; Held, Katharina; Nogueira Freitas, Ana Cristina; Janssens, Annelies; Voets, Thomas; Vriens, Joris (19 May 2020). "Gain of channel function and modified gating properties in TRPM3 mutants causing intellectual disability and epilepsy" . eLife . 9 : e57190. doi :10.7554/eLife.57190 . ISSN 2050-084X . PMC 7253177 . PMID 32427099 .
^ Becker, Lena-Luise; Horn, Denise; Boschann, Felix; et al. (2023). "Primidone improves symptoms in TRPM3-linked developmental and epileptic encephalopathy with spike-and-wave activation in sleep" . Epilepsia . 64 (5): e61 – e68 . doi :10.1111/epi.17586 . PMID 36929095 . S2CID 257581570 .
^ Krügel, Ute; Straub, Isabelle; Beckmann, Holger; Schaefer, Michael (2017). "Primidone inhibits TRPM3 and attenuates thermal nociception in vivo" . Pain . 158 (5): 856– 867. doi :10.1097/j.pain.0000000000000846 . PMC 5402713 . PMID 28106668 .
^ Gauthier, LW; Chatron, N; Cabet, S; Labalme, A; Carneiro, M; Poirot, I; Delvert, C; Gleizal, A; Lesca, G; Putoux, A (November 2021). "Description of a novel patient with the TRPM3 recurrent p.Val837Met variant" . European Journal of Medical Genetics . 64 (11): 104320. doi :10.1016/j.ejmg.2021.104320 . PMID 34438093 .
^ Kang, Q; Yang, L; Liao, H; Yang, S; Kuang, X; Ning, Z; Liao, C; Chen, B (1 June 2021). "A Chinese patient with developmental and epileptic encephalopathies (DEE) carrying a TRPM3 gene mutation: a paediatric case report" . BMC Pediatrics . 21 (1): 256. doi :10.1186/s12887-021-02719-8 . PMC 8167971 . PMID 34074259 .
^ Sundaramurthi, JC; Bagley, AM; Blau, H; Carmody, L; Crandall, A; Danis, D; Gargano, M; Gustafson, AG; Raney, EM; Shingle, M; Davids, JR; Robinson, PN (8 September 2023). "De novo TRPM3 missense variant associated with neurodevelopmental delay and manifestations of cerebral palsy" . Cold Spring Harbor Molecular Case Studies . 9 (4): mcs.a006293. doi :10.1101/mcs.a006293 . PMC 10815282 . PMID 37684057 . S2CID 261620692 .
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