CADASIL: Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy Maiya Geddes, R2 February 28 th 2008

Questions this lecture will tackle 1) When should I suspect CADASIL? 1) When should I suspect CADASIL? 2) Where is the lesion (in Notch3)? 2) Where is the lesion (in Notch3)? 3) What is the role of Notch3 in vascular smooth-muscle cells? 3) What is the role of Notch3 in vascular smooth-muscle cells? 4) How can a skin biopsy be useful in a disorder exclusive to the CNS? 4) How can a skin biopsy be useful in a disorder exclusive to the CNS? 5) Does Notch play a role in other disorders? 5) Does Notch play a role in other disorders?

When to suspect CADASIL Symptoms Symptoms 1) Migraine with aura (38% Caucasian and 8.3% Korean) 1) Migraine with aura (38% Caucasian and 8.3% Korean) 2) Stroke-like episodes age ) Stroke-like episodes age ) Early cognitive impairment (Peters 2005) and dementia (80% over 65 years) 3) Early cognitive impairment (Peters 2005) and dementia (80% over 65 years) 4) Affective disorders (20%), Psychosis 4) Affective disorders (20%), Psychosis Seizures (10%) Seizures (10%) Pregnancy complications (Roine 2005) Pregnancy complications (Roine 2005) Gait disorder Gait disorder Parkinsonism Parkinsonism

Clinical Spectrum Mean age of onset years (Kalimo 1999) Mean age of onset years (Kalimo 1999) Peak of first stroke years Peak of first stroke years Death age 53 males, 59 females (Dichgans 1998) Death age 53 males, 59 females (Dichgans 1998) Many ethnic groups affected Many ethnic groups affected Differential Diagnosis Differential Diagnosis Binswanger’s disease (HTN) Binswanger’s disease (HTN) MELAS (cortical/occipital infarcts) MELAS (cortical/occipital infarcts)

Radiologic Correlation Lacunes in white matter and deep gray Lacunes in white matter and deep gray Periventricular (96%), brainstem, external capsule, corpus callosum, frontal, spinal cord Periventricular (96%), brainstem, external capsule, corpus callosum, frontal, spinal cord Increased T2 white matter hyperintensities in asymptomatic Increased T2 white matter hyperintensities in asymptomatic Microbleeds in 31% of symptomatic (Oberstein 2001) Microbleeds in 31% of symptomatic (Oberstein 2001) Cerebral Angiography contraindicated Cerebral Angiography contraindicated Disability associated with ( Viswanathan 2007 ) Disability associated with ( Viswanathan 2007 ) volume of lacunar lesions, cerebral microhemorrhages, bp volume of lacunar lesions, cerebral microhemorrhages, bp

Mapping (Joutel Nature 1996) 19 p p NOTCH3 NOTCH3 Gain of function mutation Gain of function mutation

Predicted Protein Structure of Notch3 Transmembrane Protein Transmembrane Protein 33 Exons 33 Exons 2321 Amino Acids 2321 Amino Acids Federico Neurol Sci 2005

Predicted Protein Structure of Notch3 Federico Neurol Sci 2005 Transmembrane Region

Predicted Protein Structure of Notch3 Federico Neurol Sci 2005 Extracellular Domain Intracellular Domain

Where is the Lesion? Joutel Lancet % of Missense Point mutations are in Exon 4 (Peters 2005)

Haplotype Analysis Joutel et al. Lancet 1997 Joutel et al. Lancet 1997 Unpaired reactive cysteine residue Unpaired reactive cysteine residue Inappropriate disulfide bonding? Inappropriate disulfide bonding? Change in three-dimentional structure Change in three-dimentional structure

Disulphide Bridge

Notch3 in vascular smooth-muscle Abnormal accumulation in eosinophilic deposits Abnormal accumulation in eosinophilic deposits Thickened tunica media Thickened tunica media Infarcts from thickened and fibrotic wall of small and medium penetrating arteries Infarcts from thickened and fibrotic wall of small and medium penetrating arteries Notch3 required for differentiation and maturation of VSMC (Domenga 2004) Notch3 required for differentiation and maturation of VSMC (Domenga 2004) Impaired cerebral blood flow reactivity and cerebrovascular resistance in knockout mice Impaired cerebral blood flow reactivity and cerebrovascular resistance in knockout mice

Skin Biopsy in CADASIL Generalized arteriopathy Generalized arteriopathy Skin biopsy 96% sensitive 100% specific (Joutel 2001) Skin biopsy 96% sensitive 100% specific (Joutel 2001) Granular Osmiophilic Material deposits Granular Osmiophilic Material deposits

Small vessel arteriopathy

Gross Pathology Kalimo 1999

Notch Signaling CBF 1

Notch3 Mutations show differential Jagged1 binding and RBP/JK transcriptional activity (Joutel 2004) Mutations show differential Jagged1 binding and RBP/JK transcriptional activity (Joutel 2004) Notch3 important during development Notch3 important during development Highly conserved Highly conserved Cell fate (astroglia), organogensis, vasculogenesis Cell fate (astroglia), organogensis, vasculogenesis Notch active in mature astroglia and prevents neurite outgrowth (Sestan Science 1999) Notch active in mature astroglia and prevents neurite outgrowth (Sestan Science 1999) Same signaling pathway as Presenillin 1 Same signaling pathway as Presenillin 1 PS 1 mediated proteolytic cleavage of Notch 1 PS 1 mediated proteolytic cleavage of Notch 1

Binding of Notch to ligand triggers proteolytic cleavage Hayward

Other Notch Signaling Disorders (Gridley 2003) Notch1 in adult T-cell leukemia Notch1 in adult T-cell leukemia Alagille syndrome Alagille syndrome Mutation in Jagged-1 or Notch2 Mutation in Jagged-1 or Notch2 hepatic ductular hypoplasia, pulmonic valvular stenosis, neonatal jaundice, butterfly vertebrae, retinal changes, absent reflexes hepatic ductular hypoplasia, pulmonic valvular stenosis, neonatal jaundice, butterfly vertebrae, retinal changes, absent reflexes Spondylocostal Dysostosis Spondylocostal Dysostosis DLL3 gene mutation at 19q13 DLL3 gene mutation at 19q13 Rib and vertebral anomalies “crab-like” spine Rib and vertebral anomalies “crab-like” spine

In Summary Mutation in extracellular domain of NOTCH3 (chromosome 19) Mutation in extracellular domain of NOTCH3 (chromosome 19) Lone cysteine prevents disulphide bonding and dimerization Lone cysteine prevents disulphide bonding and dimerization Accumulation in VSMC Accumulation in VSMC Obliteration of small and medium arteries Obliteration of small and medium arteries Lacunes in white matter and deep gray Lacunes in white matter and deep gray 1) Migraine with aura 2) Stroke 3) Depression 4) Dementia 1) Migraine with aura 2) Stroke 3) Depression 4) Dementia

Physician and Patient Resources OMIM Pubmed OMIM Pubmed CADASIL foundation website: CADASIL foundation website: Leukodystrophy foundation: Leukodystrophy foundation: CADASIL support group: CADASIL support group: