A Natural History Study of the Gangliosidoses

Neuropsychological testing data will be collected at baseline and annually, that measure fine and gross motor skills, visual tracking and attention, verbal and non-verbal communication, and emotional and social behaviors. For infantile and juvenile Tay-Sachs disease, Sandhoff disease and GM1 gangliosidosis-affected subjects, age- and ability-appropriate neurobehavioral and neurodevelopmental testing will include instruments such as the Bayley Scales of Infant Development (Third Edition), and the Vineland Adaptive Behavior Scales.

If either of the following diagnostic measures have been performed in the course of subjects' clinical care not connected with this study, the resulting data will be collected: for Tay-Sachs and Sandhoff disease-affected patients, levels of hexosaminidase enzyme activity; or for GM1 gangliosidosis-affected patients, levels of β-galactosidase enzyme activity. Determinations of these enzyme activity levels are a requisite part of the diagnostic process in all of the gangliosidosis diseases.

If any medications are given to subjects during the course of subjects' clinical care not connected with this study, the medications will be identified, quantified and recorded.

Clinical assessments will be performed that measure initial symptomology, along with the appearance and evolution of symptoms over time. For infants and juveniles, these may include: evaluation of motor control, gain and/or loss of developmental milestones, hyperacusis, seizures, macrocephaly, the appearance of retinal "cherry-red spots" ascertained by ocular exam, personal interaction, and reflexes.

For adults, assessments may include: coordination, psychological disorder, verbal skills, muscle wasting with weakness, fasciculations, and posture abnormalities.

For infantile and juvenile Tay-Sachs disease, Sandhoff disease and GM1 gangliosidosis-affected subjects, if any MRI brain imaging is performed during the course of subjects' clinical care not connected with this study, these MRI brain imaging data will be captured for this study. Any developmental abnormality, and the volumes of specific brain structures imaged, will be measured and the resulting data recorded. If data from multiple MRI examinations performed at different times in any given patient's life become available, the resulting brain structure measurements will be compared across time, and analyzed in order to reveal progressive changes in brain structure, if any have occurred.

If any subject's genetic mutation(s) that are responsible for their gangliosidosis disease are identified during the course of subject's clinical care not connected with this study, that genetic mutation information will be collected for this study.

If the following biomarker measures are performed in the course of subjects' clinical care not connected with this study, the resulting data will be collected: plasma and/or cerebrospinal fluid chitotriosidase enzyme activity levels. If these measures are performed repeatedly at different times in the course of subjects' clinical care not connected with this study, the resulting data will be collected each time.

If either of the following diagnostic measures have been performed in the course of subjects' clinical care not connected with this study, the resulting data will be collected: for Tay-Sachs and Sandhoff disease-affected patients, levels of GM2 ganglioside; or for GM1 gangliosidosis-affected patients, levels of GM1 ganglioside.

For adult-onset gangliosidosis-affected subjects, neuropsychological testing will be performed at baseline and annually as part of this study. Neuropsychological testing data will be collected using instruments including, but not limited to, the Wechsler Abbreviated Scale of Intelligence and the Test of Variables of Attention ("TOVA"). The resulting data will be recorded and compared across time, and analyzed in order to reveal progressive changes in subjects' neurocognitive status, if any have occurred.

For adult-onset gangliosidosis-affected subjects, an MRI examination of the head will be performed at baseline and annually as part of this study. The volumes of specific brain structures imaged will be measured and recorded. These brain structure measurements will be compared across time, and analyzed in order to reveal progressive changes in brain structure, if any have occurred.