hereditary neuropathies
TRANSCRIPT
HEREDITARY
NEUROPATHIES
Classification & Diagnosis
BY
AMR HASAN ELHASANY
Ass. Lecturer of Neurology –Cairo University
2008
HEREDITARY NEUROPATHIES
A) Non Syndromic Hereditary Neuropathies:
1- Hereditary Motor & Sensory Neuropathies (CMT).
2- Hereditary Neuropathy with liability to Pressure Palsy (HNPP)
3-Hereditary Sensory & Autonomic Neuropathies (HSAN).
4- Distal Hereditary Motor Neuropathies (HMN).
B) Syndromic Hereditary Neuropathies:
HEREDITARY NEUROPATHIES
A) Non Syndromic Hereditary Neuropathies:
1- Hereditary Motor & Sensory Neuropathies (CMT).
2- Hereditary Neuropathy with liability to Pressure Palsy (HNPP)
3-Hereditary Sensory & Autonomic Neuropathies (HSAN).
4- Distal Hereditary Motor Neuropathies (HMN).
B) Syndromic Hereditary Neuropathies:
1) Hereditary Motor & Sensory Neuropathies
=CMT
CMT Type 1
CMT Type 2
CMT Type 3
CMT Type 4
CMT Type 5
CMT Type 6
CMT Type 7
XL CMT
1) Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy (CMT)
Type1:
Subtypes
Disorder Pattern of
inheritance Protein Location
CMT 1A AD PMP-22 17p11
CMT 1B AD P0 1q22
CMT 1C AD LITAF 16p13
CMT 1D AD EGR2 10q21
CMT 1E AD
P0 protein; 1q22
CMT 1F AD Neurofilament light
chain
8p21
1) Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy (CMT)
Type 1:
Clinical Picture
(CMT) Type 1A:
1st or 2nd decade.
Symmetrical distal LL weakness (intrinsic foot, peroneal & ant tibial muscles) Champaign bottle shape
UL involvement in 2/3 of cases.
↓ Reflexes
Hypertrophic nerves
± UL Tremors = (Rousy lévy syndrome)
Retain ambulance for life
1) Hereditary Motor & Sensory Neuropathies
(CMT) Type 1B, 1C, 1D,1E & 1F:
Clinically similar to 1A with varying severity
Electrophysiology: Demyelinating
↓ NCV ( Cut off between CMT 1 & 2 38 m/sec)
Biopsy: Onion bulb appearance
1)Hereditary Motor & SensoryNeuropathies
Hereditary Motor & Sensory Neuropathy(CMT)Type 2 : Subtypes
Disorder Pattern of inheritance Gene Location
CMT 2A AD KIF1Bβ 1p36
CMT 2B AD RAB7 3q13
CMT 2C AD 12q23-q24
CMT 2D AD GARS 7p15
CMT 2E AD NF-68 8p21
CMT 2F AD HSPB1 (HSP 27) 7q11
CMT 2G AD 12q12
CMT 2L AD HSPB8 12q24
AR-CMT2A AR Lamin A/C 1q21
AR-CMT2B AR 19q13
Andermann AR KCC3 15q13
1)Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy(CMT)Type 2 :
Clinical picture
Disorder Clinical picture
CMT 2A
Onset of neuropathy by 10yr of age;
progresses to distal weakness and atrophy
in legs; mild sensory disturbance
CMT 2B Onset 2nd- 3rd decade; severe sensory
loss with distal ulcerations.
CMT 2C Vocal cord and diaphragmatic
weakness
1)Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy(CMT)Type
2 : Clinical picture
CMT 2D Arm>leg weakness; onset in 2nd-3rd
decade.
CMT 2E Variable onset and severity; ranging from
DSS-like to CMT-2 phenotype
CMT 2F Severe distal weakness & Fasciculations
CMT 2G Proximal >distal weakness
CMT 2L Onset 15 to 33 years , Distal weakness
1)Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy(CMT)Type
2 : Clinical picture
AR-CMT2A
Onset of neuropathy in 2nd decade;
progresses to severe distal weakness and
atrophy
AR-CMT2B 3rd & 4th decade,Distal weakness
Andermann 1st decade,Hypotonia
1) Hereditary Motor & Sensory Neuropathies
b- Hereditary Motor & Sensory Neuropathy (CMT) Type 2:
Electrophysiology: Axonal
SNAP: ↓ Amplitude or even absent
Biopsy: Preferential loss of large myelinated fibers without significant demyelination, there may be clusters of of regenerating myelinated fibers
1)Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy(CMT)Type
3 : Subtypes & Clinical picture
Disorder Locus;Gene Clinical picture
DSS=Dejerene-
Sottas
syndrome
PMP22,MPZ,GJB
DGR2,NEFL
(dominant)
PRX. MTMR2
(recessive)
Onset before 3yr age
with delayed motor
development, severe
Weakness, atrophy,
and sensory loss
Congenital
Hypomyelinating
Neuropathy
(CHN)
PMP22, MPZ
(dominant); EGR2
(recessive)
Hypotonic at birth,
developing into
clinical picture often
similar to DSS
1) Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy (CMT)
Type 3 :
Electrophysiology: Demyelinating
↓ NCV < 10 m/sec
Biopsy: Prominent Onion bulb appearance
1)Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy(CMT)Type
4 : Subtypes
Disorder Pattern of
inheritance
Gene; Location
CMT-4A AR GDAPI 8q13-q21;
CMT-4B1 AR MTMR2 11q22;
CMT-4B2 AR SBF2 11p15;
CMT-4C AR KIAA1985 5q23-33;
CMT-4D AR NDRG1
8q24;
1)Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy(CMT)Type
4 :
Disorder Pattern of
inheritance
Gene; Location
CMT 4E
AR EGR2 10q21
CMT 4F AR Periaxin 19q13
HMSN-Russe
(4G)
AR 10q23
CMT 4H AR FGD4 12q12
CMT 4J
AR FIG4 6q21
1)Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy(CMT)Type
4 : Subtypes
Disorder Clinical Picture
CMT-4A Early-childhood onset, progression to wheelchair
dependency; both demyelinating and axonal phenotypes
CMT-4B1 Early-childhood onset, may progress to wheelchair
dependency; focally folded myelin sheaths
CMT-4B2 Childhood onset; progressive; focally folded myelin
sheaths; glaucoma
CMT-4C Infantile to childhood onset; progressing to wheelchair
dependency
CMT-4D Childhood onset; severe disability by 50yr; hearing loss,
dysmorphic features
1) Hereditary Motor & Sensory Neuropathies
Hereditary Motor & Sensory Neuropathy (CMT) Type 4 :
Electrophysiology: Demyelinating
↓ NCV 20-30 m/sec
Biopsy:
focally folded myelin sheaths (tomacula) in type CMT-4B1
CMT-4B2
Segmental demyelination
Onion bulb appearance
Myelinated axon loss: Large > Small
1) Hereditary Motor & Sensory Neuropathies
XL Hereditary motor & sensory neuropathy (CMT)
Xq13.1; CJB1 (Connexin 32)
Clinically:
Phenotypically similar to CMT 1
Males are more severely affected
Affected females -- mild or asymptomatic
Transient ataxia ,dysarthria
CNS white matter abnormalities on MRI studies
Electrophysiology:
↓ NCV in males
↓ NCV & amplitudes in females
Abnormal BAEP
1) Hereditary Motor & Sensory Neuropathies
CMT 5: HMSN + Pyramidal signs
CMT 6: HMSN + Optic atrophy
CMT 7: HMSN + Retinitis Pigmentosa
HEREDITARY NEUROPATHIES
A) Non Syndromic Hereditary Neuropathies:
1- Hereditary Motor & Sensory Neuropathies (CMT).
2- Hereditary Neuropathy with liability to Pressure Palsy (HNPP)
3-Hereditary Sensory & Autonomic Neuropathies (HSAN).
4- Distal Hereditary Motor Neuropathies (HMN).
B) Syndromic Hereditary Neuropathies:
2- Hereditary Neuropathy with liability to Pressure
Palsy (HNPP) Genetics
AD , 17P11.2 ,PMP 22
Clinically:
2nd or 3rd decade
↑ susceptibilityof PN to mechanical traction ,compression or minor trauma
Recurrent sudden painless episodes of isolated mononueropathy commonly affecting
Common peroneal, brachial plexus,radial& median nerves
Complete recovery in days or weeks
Less common presentations
-Progressive monoeuropathy
-Chronic sensory polyneuropathy
-Chronic sensory motor neuropathy
-Transient positional sensory symptoms
2- Hereditary Neuropathy with liability to
Pressure Palsy (HNPP)
Electrophysiology:
Prolonged distal motor latencies with focal slowing of ulnar & fibular nerve at the compression sites
Diffuse reduction of sensory nerve action potential amplitudes
Biopsy:
Focal sausage-like thickening of myelin termed Tomacula due to redundant myelin loop as a result of overgrowth of myelin spiral
HEREDITARY NEUROPATHIES
A) Non Syndromic Hereditary Neuropathies:
1- Hereditary Motor & Sensory Neuropathies (CMT).
2- Hereditary Neuropathy with liability to Pressure Palsy (HNPP)
3-Hereditary Sensory & Autonomic Neuropathies (HSAN).
4- Distal Hereditary Motor Neuropathies (HMN).
B) Syndromic Hereditary Neuropathies:
3- Hereditary Sensory & Autonomic
Neuropathies (HSAN)
Subtypes
Disorder
Pattern of
inheritance Gene Location
I AD
SPTLC1 9q22
II AR
HSN2 12p13
III AR
IKBKAP 9q31
IV AR TRKA/ NGF
receptor 1q21
V AR
3- Hereditary Sensory & Autonomic Neuropathies
(HSAN)
Hereditary Sensory & Autonomic Neuropathies (HSAN) type I
Clinically:
2nd 4th decade
Superficial & deep sensory loss affecting feet & legs acrodystrophic neuropathy= Acromutilation
Lancinating or shooting pain
± Distal muscle weakness ( D.D. CMT type 2B)
Electrophysiology: Axonal
SNAP Amplitude ↓
Motor CV NL but CMAP Amplitude may ↓ in late stages
Biopsy: Sural N biopsy : Severe loss of unmyelinted & small myelinated axons and to lesser degree loss of large myelinated fibers.
3- Hereditary Sensory & Autonomic Neuropathies
(HSAN)
Hereditary Sensory & Autonomic Neuropathies (HSAN) type II
Clinically:
Started in infancy
Panmodal sensory affection -> Acromutilation
Dysautonomia
Variable features : spastic para , retinitis pigmentosa ,motor weakness or keratitis
Electrophysiology: Axonal
SNAP Amplitude ↓
Biopsy: Sural N biopsy : loss of large & small axons
3- Hereditary Sensory & Autonomic Neuropathies
(HSAN)
Hereditary Sensory & Autonomic Neuropathies (HSAN) type III =Familial Dysautonomia = Riley Day Syndrome
Clinically:
Childern of Ashkenazi Jewish ethnicity
Autonomic > sensory
Begin at birth ( poor feeding, esophageal dysmotility ,vomiting ,recuurent fever & chest infection)
Emotional stimuli provoke episodic hypertension, profuse sweating &marked skin blotching due to defective autonomic control
Defective lacrimation ,absence of tongue papillae
Hypotonia delayed motor milestones, gait ataxia, stunted growth & scoliosis
Potentially life threatening condition due to aspiration pneuomonia, autonomic crises
3- Hereditary Sensory & Autonomic Neuropathies
(HSAN)
Hereditary Sensory & Autonomic Neuropathies (HSAN) type III =Familial Dysautonomia = Riley Day Syndrome
Electrophysiology: Axonal
SNAP Amplitude ↓
Biopsy:
Sural N biopsy : loss of small & large axons
Hereditary Sensory & Autonomic Neuropathies
(HSAN)
Hereditary Sensory & Autonomic Neuropathies (HSAN) type IV
Clinically:
Congenital insensitivity to pain
Anhidrosis
Recurrent fever
Self mutilating behaviour
Mild MR
Loss of C axons
Electrophysiology:
SNAP are preserved
Biopsy: Sural N biopsy : loss of myelinted & unmyelinated axons
Hereditary Sensory & Autonomic Neuropathies
(HSAN)
Hereditary Sensory & Autonomic Neuropathies (HSAN) typeV
Clinically:
Congenital, or Early childhood
Absence of pain
No anhidrosis
Loss of Aδ-axons
Electrophysiology:
SNAP are preserved
Biopsy: Sural N biopsy : SELECTIVE loss of small myelinted fibers
Other Hereditary Sensory Neuropathies
Disorder gene locus inheritance onset clinical
Absent pain NGF-b 1p13 Recessive Early childhood
to Adult
Absence of
pain
No anhidrosis
Inability to
experience pain
SCN
9A 2q24 Recessive Congenital
Absence of
pain
No anhidrosis
Erythromelalgia SCN
9A 2q24 Dominant Childhood
Pain, distal
Episodic
Biemond ataxia Dominant 19 to 30 years Sensory loss
Ulcero-mutilation Dominant 5 to 30 years Acromutilation
Spastic
paraparesis 5p15 Recessive 1 to 5 years Acromutilation
Other Hereditary Sensory Neuropathies
Sensory PN + Hearing loss: Connexin-31; 1p35
Sensory PN + Deafness: Xq23
HSMN + Ataxia: 7q22
HSN + Cough & GE reflux
HEREDITARY NEUROPATHIES
A) Non Syndromic Hereditary Neuropathies:
1- Hereditary Motor & Sensory Neuropathies (CMT).
2- Hereditary Neuropathy with liability to Pressure Palsy (HNPP)
3-Hereditary Sensory & Autonomic Neuropathies (HSAN).
4- Distal Hereditary Motor Neuropathies (HMN).
B) Syndromic Hereditary Neuropathies:
4- Distal Hereditary Motor Neuropathies
(HMN)= Distal Spinal Muscular Atropthy (SMA).
Subtypes &Clinical picture:
Disorder Gene/Locus Clinical picture
HMN-5 7p; GARS Arm> leg weakness; onset in 2nd- 3rd
decade; no sensory involvement
HMN 7 2q14 Vocal cord involvement
HMARD 11q13; Distal infantile SMA with diaphragm
paralysis
HMNJ 9p21; 1-p12 Childhood-onset distal weakness (Jerash type)
HMN 2p13;
DCTNl
Progressive hand >leg weakness and atrophy,
vocal fold paralysis & facial weakness
HEREDITARY NEUROPATHIES
A) Non Syndromic Hereditary Neuropathies:
1- Hereditary Motor & Sensory Neuropathies (CMT).
2- Hereditary Neuropathy with liability to Pressure Palsy (HNPP)
3-Hereditary Sensory & Autonomic Neuropathies (HSAN).
4- Distal Hereditary Motor Neuropathies (HMN).
B) Syndromic Hereditary Neuropathies:
B) Syndromic Hereditary Neuropathies
1) Demyelinating Dominant
Disorder Gene / Locus Associated
features
Wardeenburg
type IV
22q13;
SOX10
CNS & PNS
dysmyelination
Hirschsprung
disease
B) Syndromic Hereditary Neuropathies
2) Demyelinating Recessive
Disorder Gene / Locus Associated features
Metachromatic
leukodystrophy
22q13;
(ArylsulfataseA)
Optic atrophy
Mental retardation
Hypotonia
Globoid cell
leukodystrophy
(Krabbe's)
14q31;(Galactosyl
ceramide -
galactosidease)
Spasiticity,
Optic atrophy
Mental retardation
B) Syndromic Hereditary Neuropathies
2) Demyelinating Recessive
Disorder Gene / Locus Associated features
Refsum's disease 10 pter-p11.2
PAHX (Phytanoyl-
CoA hydroxylase)
& 7q21-22; PEX7
(Peroxin-1)
Deafness
Retinting pigmentosa,
Ichthyosis
heart failure
Merosin
deficiency
6q 22; LAMA2
(laminin-2)
Neuropathy and
muscular dystrophy
B) Syndromic Hereditary Neuropathies
3) Axonal dominant
Disorder Gene / Locus Associated features
Familial
Amyloidotic
Neuropathy
(FAP-I &
FAP-II
18q21; TTR
(Transthyretin)
Painful axonal neuropathy;
other organs involved;
FAP-II also causes carpal
tunnel syndrome
FAP-III"lowa" 11q23; ApoAl
(Apoliporotein
A1)
Nephropathy, liver disease
FAP- IV
"Finnish"
9q32-q34; AGel
(Gelsolin)
Corneal dystrophy, cranial
neuropathies
B) Syndromic Hereditary Neuropathies
3) Axonal dominant
Disorder Gene / Locus Associated features
Acute
Intermittent
Porphyria
11q23.3; PBGD
(Porphobillino
gen deaminase
Acute neuropathy follows
abdominal crises;
psychosis; depression;
dementia; seizures
Coproporphyria 3q12;CPO
(Copropophrin
ogen 3
oxidease)
Skin photosensitivity,
psychosis, crises of acute
neuropathy and
abdominal pain
Variegate
Porphyria
3q12;CPO
(Coproporphur
inogen 3
oxidease)
South Africa; similar to
acute intermittent
prophyria
B) Syndromic Hereditary Neuropathies
3) Axonal dominant Disorder Gene / Locus Associated
features
Fabry's disease Xq22;GLA
(galactosidase)
Angiokeratoma
Pain
Stroke
Renal failure
Cardiomyopathy
Hereditary
Neuralgic
Amyotrophy
17q25 Painful episodes of
brachial palsy,
dysmorphic features
B) Syndromic Hereditary Neuropathies
4) Axonal Recessive
Disorder Gene /
Locus
Associated
features
Hereditary
tyrosinemia
type 1
15q23-q25;
FAH
(Fumaryl-
Acetoacetase)
Hepatic and Renal
disease,
Cardiomyopathy
Giant axonal
neuropathy
16q24; GANI
(Gigaxonin)
Kinky/curly hair
CNS features
UMNL, Optic atrophy,
Nystagmus,Ataxia
Mental retardation,
B) Syndromic Hereditary Neuropathies
4) Axonal Recessive
Disorder Gene / Locus Associated
features
Abetalipoproteinemia 4q24; MTP
(microsomal
triglyceride
transfer protein)
Ataxia,
Acanthocytosis
Analphalipoproteinemia
(Tangier's disease)
9q31; ABC1
(AtP- binding
cassette
transporter)
Orange tonsils,
Organomegaly
Atherosclerosis
, Painless
ulcerations
B) Syndromic Hereditary Neuropathies
4) Axonal Recessive Disorder Gene / Locus Associated features
Cowchock's
syndrome
Xq24-26 Mental retardation
(60%)
Deafness
Congenital
Catarcts, Facial
Dysmophism
Neuropathy
(CCFDN;
18 q23-qter; CTDP1
(intron 6)
Cataracts, microcornea,
Facial dysmorphism
Skeletal deformities
Other Syndromic Hereditary Axonal
Neuropathies
Ataxia telangectasia
Cerebrotendinous xanthomatosis
Chediak-Higashi
Friedreich Ataxia
Glycogenosis, Type 3
Mitochondrial: MNGIE; NARP; Leigh; Other
Neuroacanthcytosis
Brachial Plexopathy
Diagnosis Of Hereditary
Neuropathies
Based on Clinical Presentation and
Electrophysiological Findings
Diagnosis Of Hereditary Neuropathies
History taking (hereditary cause is suggested)
Examination
Lab work to exclude causes of acquired neuropathies
Neurophysiological study
Biopsy
Genetic study
Recurrent Hereditary Neuropathies
Hereditary Neuropathies Liability to Pressure
Palsy
Brachial Plexopathy
Refsum
Porphyria
Hereditary Neuropathies affecting UL>LL
HMN 5A
CMT 2D
HMN 5B
Amyloidosis (Carpal
tunnel syndrome)
Hereditary Neuropathies Affecting Motor
Neurones
HMN-5A
HMN 7
HMARD
HMNJ
HMN
Hereditary Neuropathies associated with skin
manifestations
Amyloidosis :Petechiae or purpura
Refsum: Ichthyosis
Sensory neuronopathies: Ulcers
Coproporphyria: Skin photosensitivity,
Fabry: Angiokeratoma
Hereditary Neuropathies Affecting eye
CMT-4B2 : Glaucoma
CMT 6 : optic atrophy
CMT 7 : RP
Mitochondrial disorders
Leukodystrophies: optic atrophy
Refsum: RP
FAP- IV: Corneal dystrophy
Congenital Catarcts, Facial Dysmophism Neuropathy (CCFDN) : Cataract
Ataxia Telangectasia
Hereditary Neuropathies associated with
Hearing Loss
X-linked
Cowchock
HMSN X (Connexin 32)
Recessive
CMT 4D (Lom)
Refsum
Xeroderma Pigmentosum
CEDNIK
Dominant
CMT 1A
CMT 1B
CMT 2E
CMT-4D
Dejerine-Sottas (Dominant)
Hereditary Neuropathies associated with
thickened nerves
Demyelinating
HMSN I & III
Refsum
Neurofibromatosis
Hereditary Neuropathies associated with GIT
troubles
HSN + Cough & GE reflux
Mitochondrial: MNGIE & Variants
Riley-Day (HSAN3)
Hereditary Neuropathies associated with
Facial Nerve palsy
Amyloid: Gelsolin
Tangier disease
Hereditary Neuropathies associated with
Dysmorphic Features
CMT-4D
Hereditary Neuralgic Amyotrophy
Congenital Catarcts, Facial Dysmophism
Neuropathy (CCFDN;
Hereditary Neuropathies associated with
Vocal cord affection
HMSN II C
HMN 7
Hereditary Axonal Neuropathies
HMSN: II ,V ,VI
HSAN
Spinal muscular atrophy: Proximal; Distal
Amyloidosis
Porphyria
Fabry's
Hereditary tyrosinemia type 1
Giant Axonal Neuropathy
A-beta-lipoproteinemia
An-α-lipoproteinemia (Tangier's)
Cowchock's syndrome
Congenital Catarcts, Facial Dysmophism Neuropathy (CCFDN;
Ataxia telangectasia
Cerebrotendinous xanthomatosis
Chediak-Higashi Friedreich Ataxia
Mitochondrial: MNGIE; NARP; Leigh; Other
Hereditary Demyelinating Neuropathies
HMSN type I, III, IV, XL
HNNP
Leukodystrophies
Refsum
Wardeenburg type IV
Clinical Case
40ys old female patient presenting with gradual progressive weakness both UL & LL, D>P, UL>LL associated with distal wasting
NC study showed axonal motor affection with no sensory affection
keywords
UL involvement
Pure motor
Axonal
Hereditary Neuropathies Affecting Motor
Neurones
HMN-5A
HMN 7
HMARD
HMNJ
HMN
Hereditary Neuropathies affecting UL>LL
HMN-5A
CMT 2D
HMN 5B
Amyloidosis (Carpal tunnel syndrome)
Hereditary Axonal Neuropathies
HMSN: II
HSAN
HMN =Spinal muscular atrophy: Proximal; Distal
Amyloidosis
Porphyria
Fabry's
Hereditary tyrosinemia type 1
Giant Axonal Neuropathy
A-beta-lipoproteinemia
An-α-lipoproteinemia (Tangier's)
Cowchock's syndrome
Congenital Catarcts, Facial Dysmophism Neuropathy (CCFDN;
Ataxia telangectasia
Cerebrotendinous xanthomatosis
Chediak-Higashi Friedreich Ataxia
Mitochondrial: MNGIE; NARP; Leigh; Other
Online Mendelain Inheritance in Man
(OMIM):
www.ncbi.nlm.nih.gov/Omim/
Neuromuscular:
www.neuro.wustl.edu/neuromuscular/
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