Table 5 Comparison of results of clinical and neuropathological studies of idiopathic autism and dup(15) autism

Autism prevalence and severity

Clinical data

81 % of subjects met criteria for autism and 92 % for ASD [12, 14]. Autism diagnosed in 69 % of subjects [36]

Mild 55 %; Moderate 30 %, Severe 15 % [84]

Postmortem study

Autism diagnosed in 89 % of children and young adults

100 %

Intellectual disability

Clinical data

5/5 severe-moderate ID [85, 86]

IQ < 70, 31 %; IQ 71–85, 23 %; IQ > 85, 46 % [84]

Postmortem study

Profound, ID in 67 %; severe & moderate ID in 33 %

Moderate in 3 cases with tested IQ

Epilepsy

Clinical data

Epilepsy in 63 % [66]

Epilepsy in 33 % [71]. Epileptiform activity in 31 % of autistic children without epilepsy [75]

Postmortem study

Epilepsy in 87 % including intractable epilepsy in 62 %. SUDEP in 87 % of cases

Epilepsy in 50 % of subjects SUDEP in one case/eight (12 %)

Brain weight

Postmortem study

1,215 g

1,611 g (1,376 g in control subjects)

Focal developmental defects [46]

Heterotopias (alveus, CA4, DG)

89 %

10 % (p < 0.001)

DG dysplasia

89 %

10 % (p < 0.001)

Cerebral cortical dysplasia

0 %

50 % (p < 0.03)

Cerebellar heterotopias

56 %

60 % (ns)

Cerebellar flocculus dysplasia

75 %

50 % (ns)

Subependymal nodular dysplasia

22 %

10 % (ns)

-

In 14/16 (87 %) regions in 4 to 8 years old [60]

11/25 (44 %) regions in 9 to 26 years old

In 3/16 (19 %) regions in 11 to 23 years old [60]

-

In 4/16 (25 %) regions in 22 to 49 years old [60]