This is not a comprehensive list, simply some articles I have found along the way.
There seems to be growing evidence that excess glutamate is also involved with dyslexia.
” The first theory suggests that dyslexia might be a consequence of neuronal hyperexcitability, which contributes to learning deficits by heightened noise and instability in information processing3. This theory emphasizes the importance of balanced levels of excitation and inhibition within cortical pyramidal-interneuron networks, which support tuning to sensory input, neural timing, and information processing. Excitation–inhibition balance and the precise timing of neural activity can be disrupted by cortical hyperexcitability. On the level of neurotransmitters, this theory predicts heightened level of glutamatergic (Glu or Glx) signalling in dyslexic individuals3, since glutamate concentrations were found to be positively correlated with cortical excitability4. The loss of neuronal synchronization is hypothesized to lead to deficits in low-level temporal auditory processing, the oscillatory neural processes that sample and encode sensory information and impairments in multisensory integration, all of which are key components of reading development.” https://www.nature.com/articles/s41598-019-41473-x
Glutamate and Choline Levels Predict Individual Differences in Reading Ability in Emergent Readers “The current study is the first to examine neurochemistry in children during the critical period in which the neurocircuits that support skilled reading are still developing. In a longitudinal pediatric sample of emergent readers whose reading indicators range on a continuum from impaired to superior, we examined the relationship between individual differences in reading and reading-related skills and concentrations of neurometabolites measured using magnetic resonance spectroscopy. Both continuous and group analyses revealed that choline and glutamate concentrations were negatively correlated with reading and related linguistic measures in phonology and vocabulary (such that higher concentrations were associated with poorer performance). Correlations with behavioral scores obtained 24 months later reveal stability for the relationship between glutamate and reading performance. Implications for neurodevelopmental models of reading and reading disability are discussed, including possible links of choline and glutamate to white matter anomalies and hyperexcitability. These findings point to new directions for research on gene-brain-behavior pathways in human studies of reading disability. http://www.haskins.yale.edu/reprints/hl1762.pdf
Neural Noise Hypothesis of Developmental Dyslexia “Developmental dyslexia (decoding-based reading disorder; RD) is a complex trait with multifactorial origins at the genetic, neural, and cognitive levels. There is evidence that low-level sensory-processing deficits precede and underlie phonological problems, which are one of the best-documented aspects of RD. RD is also associated with impairments in integrating visual symbols with their corresponding speech sounds. Although causal relationships between sensory processing, print–speech integration, and fluent reading, and their neural bases are debated, these processes all require precise timing mechanisms across distributed brain networks. Neural excitability and neural noise are fundamental to these timing mechanisms. Here, we propose that neural noise stemming from increased neural excitability in cortical networks implicated in reading is one key distal contributor to RD.” http://www.sciencedirect.com/science/article/pii/S1364661317300517
“A study conducted at the Yale and University of Connecticut-affiliated Haskins Laboratories discovered that higher levels of two neurotransmitters, glutamate and choline, were associated with lower reading proficiency in young children. Initial levels of glutamate continued to correlate with reading levels observed two years later. The finding is the first pediatric study to show that levels of chemicals in the brains of children that are beginning to learn to read can predict later reading outcomes, said Ken Pugh, president and director of research at Haskins Laboratories and study co-author.” ” Glutamate, a key neurotransmitter that has also been associated with disorders like ADHD, may contribute to impaired reading through excessive excitatory activity at high concentrations, Pugh said.” https://yaledailynews.com/blog/2014/03/25/neurotransmitters-predict-reading-ability/