Table 3.

Ages at disease onset and euthanasia for dogs with genetically defined neuronal ceroid lipofuscinosis (NCL)

Disease	Gene	Mutation	Breed	Age at Onset (Months)a	Age at Euthanasia (Months)	References
CLN1	PPT1	c.124 + 1G>A	Cane Corso	8	10	Current
CLN1	PPT1	c.736_737insC	Dachshund	8	14	25
CLN2	CLN2	c.325delC	Dachshund	7–9	12	27
CLN5	CLN5	c.619C>T	Border Collie, Australian Cattle Dog	12–23	15–29	6,28,29
CLN5	CLN5	c.934_935delAG	Golden Retriever	13–17	30–34	2
CLN6	CLN6	c.829T>C	Australian Shepherd	18	24	30
CLN7	MFSD8	c.843delT	Chinese Crested Dog, Chihuahua	12	16–24	4,5,31
CLN8	CLN8	c.491T>C	English Setter	12–14	24–27	32,33
CLN8	CLN8	c.585G>A	Australian Shepherd	11	21	3
CLN10	CTSD	c.579G>A	American Bulldog	11–36	42–66b	34,35
CLN12	ATP13A2	c.1623G>A	Tibetan Terrier	60–96	Up to 120	38,39

^aAlmost all of the ages at onset were based on reports from owners not expecting their dogs to show abnormal signs. In a research setting, trained animal technicians can identify earlier onsets. For instance, research Dachshunds with CLN2 disease show abnormal signs by 5 months of age.

^bThe late age at onset of American Bulldogs with CLN10 disease probably reflects residual cathepsin D enzymatic activity from a hypomorphic CTSD:c.585A allele.35 Sheep, mice, and human babies with nullifying CTSD mutations have congenital NCL.40, 41, 42