This website provides information on patients with mutations in the gene SLC9A1 (solute‐carrier family 9, member A1; also known as NHE1), including clinical data, molecular data, management, and research options.

SLC9A1 is located on chromosome 1p36.11 and encodes the plasma-membrane sodium (Na⁺)/proton (H⁺) exchanger 1 isoform (NHE1) that exchanges one intracellular H⁺ for one extracellular Na⁺. Its normal functions include regulation of intracellular pH homeostasis, cell volume and cell migration. Expression is widespread including in brain, kidney, intestine, as well as most other tissues.

Mutations in the SLC9A1 gene lead primarily to an autosomal recessive neurological disorder called Lichtenstein-Knorr syndrome characterised by childhood-onset gait and limb ataxia, dysmetria, adiadochokinesia, areflexia, and progressive sensorineural hearing loss with absence of speech. Cognitive impairments have been documented in some cases.

Not all individuals with a genetic variation or mutation in the SLC9A1 gene have all these features.

This website was created to share and collect information about clinic, management, and research projects to gather more knowledge and provide better treatment of patients with mutations in the SLC9A1 gene.

John Orlowski, PhD, Department of Physiology, McGill University, Montreal, Quebec, Canada, john.orlowski@mcgill.ca