Pediatric Gender Diversity Beyond the Binary: An Exploration of Gender-Affirming Care for Nonbinary and Genderqueer Youth Seen Over Time at a Single Institution Gender Center.

Purpose: The nonbinary and genderqueer (NBGQ) youth population is growing, yet scant research focuses on this distinct group. We aim to gain a deeper understanding of desired gender-affirming care and interventions pursued by NBGQ youth. Methods: A retrospective chart review of NBGQ patients seen at the University of California, San Francisco Child and Adolescent Gender Center from January 1, 2009, to December 31, 2020, was performed. Demographic information, desired gender-affirming care, and gender-affirming interventions pursued at initial and most recent visits were collected. Results: Initial visit charts of 116 NBGQ youth who attended more than one clinic visit were reviewed. In total, 48 unique genders were documented; gender evolved over time for some youth, as did desired gender-affirming care. At the most recent visit, 15 youth (12.9%) had a binary gender, and 101 youth (87.1%) had an NBGQ gender. At the initial visit, 56 youth (48.3%) were interested in gender-affirming hormone therapy, compared with 75 youth (65.6%) at the most recent visit. In addition, 21 (18.1%) and 49 (42.2%) youth were interested in surgery at the initial and most recent visits, respectively. In general, interest in interventions was higher than pursuit of interventions. Conclusion: There is vast diversity of gender and differences in desired gender-affirming care within the NBGQ youth population. Desires for gender-affirming care within the cohort changed over time, and not all those who expressed a desire for an intervention received it. The reasons are likely multifactorial, highlighting the need for expectation-free and patient-specific affirming care and research on the NBGQ youth population, while also considering barriers to care.

Modeling pain in vitro using nociceptor neurons reprogrammed from fibroblasts.

Reprogramming somatic cells from one cell fate to another can generate specific neurons suitable for disease modeling. To maximize the utility of patient-derived neurons, they must model not only disease-relevant cell classes, but also the diversity of neuronal subtypes found in vivo and the pathophysiological changes that underlie specific clinical diseases. We identified five transcription factors that reprogram mouse and human fibroblasts into noxious stimulus-detecting (nociceptor) neurons. These recapitulated the expression of quintessential nociceptor-specific functional receptors and channels found in adult mouse nociceptor neurons, as well as native subtype diversity. Moreover, the derived nociceptor neurons exhibited TrpV1 sensitization to the inflammatory mediator prostaglandin E2 and the chemotherapeutic drug oxaliplatin, modeling the inherent mechanisms underlying inflammatory pain hypersensitivity and painful chemotherapy-induced neuropathy. Using fibroblasts from patients with familial dysautonomia (hereditary sensory and autonomic neuropathy type III), we found that the technique was able to reveal previously unknown aspects of human disease phenotypes in vitro.

Intrinsic membrane hyperexcitability of amyotrophic lateral sclerosis patient-derived motor neurons.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease of the motor nervous system. We show using multielectrode array and patch-clamp recordings that hyperexcitability detected by clinical neurophysiological studies of ALS patients is recapitulated in induced pluripotent stem cell-derived motor neurons from ALS patients harboring superoxide dismutase 1 (SOD1), C9orf72, and fused-in-sarcoma mutations. Motor neurons produced from a genetically corrected but otherwise isogenic SOD1(+/+) stem cell line do not display the hyperexcitability phenotype. SOD1(A4V/+) ALS patient-derived motor neurons have reduced delayed-rectifier potassium current amplitudes relative to control-derived motor neurons, a deficit that may underlie their hyperexcitability. The Kv7 channel activator retigabine both blocks the hyperexcitability and improves motor neuron survival in vitro when tested in SOD1 mutant ALS cases. Therefore, electrophysiological characterization of human stem cell-derived neurons can reveal disease-related mechanisms and identify therapeutic candidates.

Pathways disrupted in human ALS motor neurons identified through genetic correction of mutant SOD1.

Although many distinct mutations in a variety of genes are known to cause Amyotrophic Lateral Sclerosis (ALS), it remains poorly understood how they selectively impact motor neuron biology and whether they converge on common pathways to cause neuronal degeneration. Here, we have combined reprogramming and stem cell differentiation approaches with genome engineering and RNA sequencing to define the transcriptional and functional changes that are induced in human motor neurons by mutant SOD1. Mutant SOD1 protein induced a transcriptional signature indicative of increased oxidative stress, reduced mitochondrial function, altered subcellular transport, and activation of the ER stress and unfolded protein response pathways. Functional studies demonstrated that these pathways were perturbed in a manner dependent on the SOD1 mutation. Finally, interrogation of stem-cell-derived motor neurons produced from ALS patients harboring a repeat expansion in C9orf72 indicates that at least a subset of these changes are more broadly conserved in ALS.