This document relates to methods and materials for assessing and / or treating a mammal (e.g., a human) having, or at risk of developing, a spinal condition (e.g., spinal muscular atrophy (SMA)). In some cases, a mammal can be identified as having, or as being likely to develop, a spinal condition (e.g., SMA), and, optionally, can be treated. For example, a mammal can be identified as having, or as being likely to develop, a spinal condition (e.g., SMA), based, at least in part, on the modification of nucleic acid that can encode a survival motor neuron (SMN) polypeptide (e.g., homozygous deletion of exon 7 of SMN1 nucleic acid encoding a SMN polypeptide and the genomic copy number of SMN2 nucleic acid encoding a SMN polypeptide) in a sample from a mammal and, optionally, can be treated.