Natural History Study of Infantile and Juvenile GM1 Gangliosidosis (GM1) Patients

Survival will be evaluated at the baseline visit and each subsequent visit for 3 years. This outcome measure is considered a primary outcome measure for the infantile (Type 1) GM1 population and a secondary outcome measure for the juvenile (Type 2) GM1 population.

The presence of a feeding tube and dependence on the feeding tube, if applicable, will be evaluated at the baseline visit and each subsequent visit for 3 years. This outcome measure is considered a primary outcome measure for the infantile (Type 1) GM1 population and a secondary outcome measure for the juvenile (Type 2) GM1 population.

The Vineland Adaptive Behavior Scales, Second Edition (Vineland-II) is a standard assessment for measuring personal and social skills for children and adults (birth through 90 years of age). This assessment aids in diagnosis of intellectual and developmental disabilities or delays associated with a variety of diseases/disorders. The assessment includes 5 domains. Scores for each domain and a composite adaptive behavior score are then converted to standard scores with a range of 20 to 140, with a score of 140 correlating to a high adaptive level.

Based on the outcome of the Vineland-II, each subject will be given a developmental age score that will determine whether the Bayley Scale of Infant and Toddler Development, Third Edition (BSID-III) or the Kaufman Assessment Battery for Children, Second Edition (KABC-II) is administered. Children with a developmental age of 42 months or less will be administered the BSID-III and those with a developmental age of greater than 42 months will be administered the KABC-II.

The BSID-III assesses 5 major areas of development. Each domain results in a raw score that is converted to a composite score. A higher composite score generally corresponds with higher function.

The KABC-II assesses 4 major areas of intelligence and achievement in young children. Each domain results in a raw score that is converted to a standard score. Scores from 90-109 are generally considered average, with scores higher than 109 considered to be above average.

Survival will be evaluated at the baseline visit and each subsequent visit for 3 years. This outcome measure is considered a primary outcome measure for the infantile (Type 1) GM1 population and a secondary outcome measure for the juvenile (Type 2) GM1 population.

The presence of a feeding tube and dependence on the feeding tube, if applicable, will be evaluated at the baseline visit and each subsequent visit for 3 years. This outcome measure is considered a primary outcome measure for the infantile (Type 1) GM1 population and a secondary outcome measure for the juvenile (Type 2) GM1 population.

See these outcome measures described above for full details.

The BSID-III or the KABC-II will be evaluated at the baseline visit and each subsequent visit for 3 years. This outcome measure is considered a primary outcome measure for the juvenile (Type 2) GM1 population and a secondary outcome measure for the infantile (Type 1) GM1 population.

The Pediatric Quality of Life Inventory, Version 4.0 (PedsQL) is a 21 to 45-item assessment of quality of life over the previous 30 days, based on parent/caregiver report. The inventory consists of assessments for infants, toddlers, young children, children, teens and young adults, based on the age of the subject. A lower total score indicates higher quality of life.

Motor development will be assessed in terms of six developmental milestones: sitting without support, standing with assistance, hands-and-knee crawling, walking with assistance, standing alone, and walking alone. Each milestone will be assessed as either "achieved", "not achieved" or "achieved but lost" based on clinician observation as well as parent report.

The change from baseline in presence/absence of seizures and frequency of seizures (if applicable) will be examined through review of seizure diaries recorded by parents over a three year period.

An electrocardiogram (ECG) is a test using electrodes attached to the subject's chest, arms, and legs to record the electrical activity in the heart and detect abnormalities. The clinician will note whether each ECG is normal or abnormal, and the results will be compared to the baseline ECG and tracked over time.

A lateral spine plain film involves taking an X-ray of the subject's spine to determine if there are structural abnormalities. An X-ray of the spine will be performed at the baseline visit, then every 6 months for up to three years in order to assess changes.

An echocardiogram (ECHO) uses ultrasound to produce images of the subject's heart. The ECHO report will be evaluated for changes from baseline through the course of the study.

An electroencephalogram (EEG) is a test using electrodes attached to the subject's scalp to detect abnormal activity in the brain. The EEG should be performed, if consent if provided, at each visit. The clinician will note whether each ECG is normal or abnormal, and the results will be compared to the baseline ECG and tracked over time.

If consent if provided, magnetic resonance imaging (MRI) of the brain will be obtained, without contrast, to examine changes in the total volume of the brain as well as the volumes of several brain substructures over time. The MRI may be performed under general anesthesia in this pediatric population. It is important that all procedures requiring general anesthesia are performed in close temporal proximity, while the subject is under anesthesia.

If consent if provided, magnetic resonance imaging (MRI) of the abdomen will be obtained, without contrast, to examine changes in the total volume of the liver and spleen over time. The MRI may be performed under general anesthesia in this pediatric population. It is important that all procedures requiring general anesthesia are performed in close temporal proximity, while the subject is under anesthesia.

Only if consent is not provided to obtain images of the abdomen via MRI, an abdominal ultrasound will be performed to examine changes in the total volume of the liver and spleen over time.

Blood and, if consent is given, cerebrospinal fluid (CSF)* will be collected at the baseline visit and each subsequent visit to analyze beta-galactosidase enzyme activity. The aim is to examine enzyme activity variability, change from baseline and relationship to disease progression. As this biomarker are currently under study, ranges cannot be provided at this time. Additional samples may also be stored at a biobank for future research and testing, if consent is obtained.

*Collection of CSF via a lumbar puncture is an OPTIONAL procedure conducted only at Baseline and Months 6, 12, 24 and 36.

Blood and, if consent is given, cerebrospinal fluid (CSF)* will be collected at the baseline visit and each subsequent visit to analyze hexosaminidase enzyme activity. The aim is to examine enzyme activity variability, change from baseline and relationship to disease progression, if applicable. As this biomarker are currently under study, ranges cannot be provided at this time. Additional samples may also be stored at a biobank for future research and testing, if consent is obtained.

*Collection of CSF via a lumbar puncture is an OPTIONAL procedure conducted only at Baseline and Months 6, 12, 24 and 36.

Blood and urine will be collected at the baseline visit and each subsequent visit to analyze keratan sulfate levels. The aim is to examine variability and change from baseline in the levels as well as relationship to disease progression, if applicable. As this biomarker are currently under study, ranges cannot be provided at this time. Additional samples may also be stored at a biobank for future research and testing, if consent is obtained.

If consent is given, cerebrospinal fluid (CSF)* will be collected at the baseline visit and each subsequent visit to analyze GM1 ganglioside levels. The aim is to examine variability and change from baseline in the levels as well as relationship to disease progression. As this biomarker are currently under study, ranges cannot be provided at this time. Additional samples may also be stored at a biobank for future research and testing, if consent is obtained.

*Collection of CSF via a lumbar puncture is an OPTIONAL procedure conducted only at Baseline and Months 6, 12, 24 and 36.