| Missense mutations | 53.3% of all variants; often lead to protein instability and reduced ALDP abundance |
| Frameshift mutations | ~23% of variants; generally cause complete loss of ALDP function |
| Nonsense mutations | ~10%; result in premature termination and non-functional protein |
| Splice-site mutations | ~7%; disrupt mRNA processing |
| Large deletions | ~4%; may remove single or multiple exons |
| In-frame deletions/insertions | ~3% |
| Males | Hemizygous males (one X chromosome) are affected; all males with a pathogenic *ABCD1* variant will develop some phenotype by adulthood |
| De novo mutations | Account for approximately 4-8% of cases |
| Age of onset | Typically 4-8 years, after a period of normal development |
| Early symptoms | Behavioral changes, declining school performance, visual and auditory processing difficulties |
| Progressive phase | Rapid demyelination with inflammatory infiltrates, leading to progressive cognitive and motor decline |
| Terminal phase | Vegetative state within 2-5 years of symptom onset |
| Databases | OMIMOrphanetClinicalTrialsPubMed |