Late Infantile Neuronal Ceroid Lipofuscinosis (LINCL)

Rare, autosomal recessive, fatal lysosomal storage disease with extensive CNS neurodegeneration

Caused by mutations in the CLN2 gene, coding for a tripeptidyl peptidase (TPP-I) that normally functions to remove waste membrane proteins

Prior studies have demonstrated high level, long term TPP-I expression in the brain following intracranial gene transfer using an AAV2-based vector expressing the human CLN2 cDNA (AAV2CUhCLN2)1

AAV2 mediated gene transfer to the CNS corrects the storage defect in CLN2 knockout mice2

1 Sondhi et al, ASGT Abstract #6602 Passini et al. ASGT Abstract #427

Clinical Assessment of LINCL

Challenge To develop a non-invasive strategy to assess

the efficacy of direct CNS administration of AAV2CUhCLN2 in clinical studies

Strategy Assess magnetic resonance spectroscopy as a

method to evaluate the status of the CNS in children with LINCL over time

Demographic Characteristics of Study Population

Subject Sex GenotypeAge at 1st MRS1

scan (yr)Interval between 1st and 2nd MRS (days) LINCL rating2

1 M G3556C / T3016A 8.4 74 3 (severe)

2 M G3556C / G3085A 9.2 92 3 (severe)

3 M G3556C / G3085A 6.6 127 3 (severe)

4 F C3670T / T4396G 13.6x nd1 3 (severe)

5 M G3556C / C3670T 6.2 336 5 (moderate)

6 F G3556C / G3556C 7.9 46 3 (severe)

7 F G3556C / G3556C 6.6 nd 3 (severe)

8 M G3556C / G3556C 6.0 nd 4 (severe)

9 M G3556C / T4383C 6.8 nd 4 (severe)

10 M C3670T / ? 5.0 nd 5 (moderate)

11 F G3556C / G3556C 5.4 nd 5 (moderate)

12 F C3670T / C3670T 4.4 39 4 (severe)

1 MRS = magnetic resonance spectroscopy; nd = not done2 LINCL rating scale based on Steinfeld et al, Am J Med Gen (2002); 112: 347-354

Magnetic Resonance Scan of Severe LINCL

Slice 1

Slice 2

Slice 3

Slice 4

1 2

3 4

Metabolite Levels in Voxels from Parenchyma and Ventricles Determined by Magnetic Resonance

Spectroscopy of Subject with Severe LINCL

LAC

CHO

CRNAA

CHO = cholineCR = creatineNAA = N-acetylaspartateLAC = lactic acid

Definition of Area in Cortex for Assessment by Magnetic Resonance

Spectroscopy

Metabolite concentrations assessed in voxels indicated in slice 2

Examples of Metabolites in the Cortex

BD001 Age 8

BD009, Age 5

BD005, Age 13

BD002, Age 9

CHOCR

NAA LAC CHOCR

NAA LAC

Metabolite Levels in the Cortex

Subject

Age

(Yr) LactateN-acetyl aspartate Creatine Choline

N-acetyl aspartate /

creatine

1 8.4 2.94 4.66 3.44 4.99 1.36

2 9.2 2.28 6.33 3.87 6.20 1.65

3 6.6 2.07 8.10 4.59 7.99 1.77

4 13.6x 17.90x 1.36 2.51 2.84 0.61

5 6.2 2.41 7.23 4.48 6.96 1.74

6 7.9 8.53 4.76 3.93 7.21 1.22

7 6.6 2.34 6.89 5.25 7.81 1.32

8 6.0 nd1 nd nd nd nd

9 6.8 2.63 7.40 6.45 8.99 1.16

10 5.0 1.31 4.72 3.01 5.01 1.59

11 5.4 3.21 10.74x 7.55 9.78 1.43

12 4.4 2.48 11.30x 8.38 11.11x 1.36

1. nd – not determined

Le

vel o

f N

-ac

ety

lasp

art

ate

LateralCaudal / rostral

0

2

4

6

8

Spatial Variation of N-acetylaspartate Levels in Subject with Severe LINCL

Due to substantial spatial variation, comparison of two MRS scans for the same subject requires careful alignment of the images

Age-dependence of Creatine and Lactate Levels in Cortex

Age (yr)

0

2

4

6

8

10

0 2 4 6 8 10 12 14

Cre

atin

e

0

5

10

15

20

0 2 4 6 8 10 12 14

Lac

tate

Subject

2

3

4

5

6

7

9

10

11

12

1

y = 8.9 - 0.53xr2 = 0.48

y = -5.1 + 1.2xr2 = 0.49

Age-dependence of Choline and N-acetylaspartate Levels in Cortex

Age (yr)

0

2

4

6

8

10

12

14

0 2 4 6 8 10 12 14

Ch

oli

ne

0

2

4

6

8

10

12

14

0 2 4 6 8 10 12 14

N-a

cety

lasp

arta

te

Subject

2

3

4

5

6

7

9

10

11

12

1

y = 12.7-0.74xr2 = 0.56

y = 13.6 - 0.90xr2 = 0.62

Reproducibility of N-acetylaspartate Level Between two MRS Scans of the Same Subject

Changes in N-acetylaspartate level are small and spatially uniform

Local increase

Local decrease

-6.0

-3.0

0.0

3.0

6.0

Ch

an

ge

in

NA

A l

ev

el

(1st s

ca

n –

2n

d s

ca

n)

Caudal Rostral

-6.0

-3.0

0.0

3.0

6.0

Ch

an

ge

in

NA

A l

ev

el

(1st s

ca

n –

2n

d s

ca

n)

Subject #1 Subject #3

Caudal Rostral

Left

Rig

ht

Left

Rig

ht

Summary Magnetic resonance spectroscopy scans of children with

LINCL show age-dependent decreases in the levels of choline, creatine and N-acetylaspartate, and an age dependent increase in levels of lactate

N-acetylaspartate provides the most reliable parameter of age-dependent changes

Duplicate MRS on the same subject can be registered, demonstrating similar local metabolite levels

Assessment of local N-acetylaspartate levels in serial MRS scans following gene transfer have the potential to show areas of the brain that are spared from progression of the disease