This study is a longitudinal and prospective study of the natural history of infantile neuroaxonal dystrophy (INAD).

After obtaining informed consent, the study participants' relevant medical records will be collected and reviewed for this study. Next, a clinic visit will be scheduled with the patient's family and an observing MD/DO/MBBS from a sponsor site to confirm and clarify information in the medical records.

A baseline evaluation of clinical status will also be performed during this visit to serve as visit one in this longitudinal, prospective natural history study. Subsequent visits will take place every 6 months, for up to 24 months. Key components of this prospective study at each visit include a neurodevelopment exam tailored for INAD, application of the CHOP-INTEND neurodevelopment scale, the Hammersmith infant neurological examination and the modified Ashworth spasticity scale as well as collection of monthly parental severity scoring and monthly home videos of activities of daily living (ADLs).

Data from this study will be pooled and presented in aggregate, without identification of individual subjects.

Inclusion Criteria:

• Male or female 18 months to 10 years of age
• Medical history consistent with the symptoms of classic INAD (onset of symptoms between the ages of 6 months and 3 years)
• Homozygous or compound heterozygous PLA2G6 variants
• Signed informed consent form (ICF) prior to entry into the registry

Exclusion Criteria:

• Diagnosis of atypical NAD (ANAD)
• Additional underlying diagnosis with features that overlap with INAD
• Unwilling or unable to allow medical record review
• Unwilling or unable to participate in serial assessments every 6 months (including deceased patients)

Living males or females with a diagnosis of classic INAD between 18 months to 10 years of age.