Transcript THE NATURAL HISTORY OF WOLF

WOLF-HIRSCHHORN SYNDROME (4p-):
HISTORIC, CYTOGENETIC,
& MEDICAL ASPECTS
Update On Advances In Knowledge
John C. Carey, MD
University of Utah
Division of Medical Genetics
Department of Pediatrics
Salt Lake City, Utah
Agatino Battaglia, MD
Stella Maris Institute for
Child & Adolescent
Neurology & Psychiatry
Pisa, Italy
Original Paper
• WHS is a MCA/DD disorder, first described by:
– Cooper H, Hirschhorn K. Apparent deletion of short
arms of one chromosome (4 or 5) in a child with
defects of midline fusion. Mammalian Chrom Nwsl
1961; 4: 14.
– Paper by Wolf et al. and Hirschhorn et al.,
Humangenetik, 1965
Wolf-Hirschhorn (4p-) Syndrome
• About 200 cases reported in literature
• Very little data on the natural history
Pediatrics 1999, 103: 830-836
Wolf-Hirschhorn (4p-) Syndrome
• FREQUENCY 1/50,000 BIRTHS
• 2F : 1M SEX PREDILECTION
Frequency of Main Characteristics of Wolf-Hirschhorn Syndrome
Exceeding 75%
Greek warrior helmet appearance of the nose
Microcephaly
Hypertelorism
Distinct Mouth
Short philtrum
Micrognathia
Mental retardation
IUGR/postnatal growth retardation
Hypotonia
Seizures
Feeding difficulties
Simple/angulated ears/pits/tags
Frequency of Main Characteristics of Wolf-Hirschhorn Syndrome
50% to 75%
Distinctive EEG abnormalities
Skeletal anomalies
Abnormal teething
Ptosis
25% to 50%
Heart defects
Hearing defects
Eye/optic nerve defect
Stereotypies
Cleft lip/palate
Structural brain anomalies
Genitourinary tract defects
Below 25%
Liver/gallbladder/gut/diaphragm anomalies
Wolf-Hirschhorn (4p-) Syndrome
• Usually there tends to be a skewing of
information to the negative.
• Families being told that their child has very
little chance for meaningful interaction with
relatives and peers; will never walk or
achieve sphincter control.
Wolf-Hirschhorn (4p-) Syndrome
• To help delineate more accurately the natural
history and to obtain better information to answer
parents’ questions in a clinical setting, we
collected information on >75 persons with WHS.
• Personally observed, or
• Clinical information gained from an exhaustive
questionnaire sent out to the families through
their national support groups in USA & Italy
(2000 – 2006).
Wolf-Hirschhorn (4p-) Syndrome
• 2 : 1 females to males
• Age range at first observation/question.
filled out: newborn to 17 years
• 20 patients followed up by us from 4
months to 22 years
Wolf-Hirschhorn (4p-) Syndrome
Birth and Family History Data
on 60 Patients
• Family histories non-contributory
• Parental ages were similar to the
general population
• Almost all patients (but one) were born
at term and were small for dates
Wolf-Hirschhorn (4p-) Syndrome
• Age at diagnosis varied between 7
months gestation and 16 years
• Most patients had at least chromosome
study before diagnosis was made
• Some patients with WHS are still being
misdiagnosed and unrecognized
Wolf-Hirschhorn (4p-) Syndrome
• WHS is caused by deletion of the distal
portion of the short arm of chromosome
4 (the minimal deleted segment causing
the phenotype is 4p16.3)
• Regular G-banding
60%
• HRB
15%
• FISH
25%
(using a probe that includes the WHCR)
Genetics of WHS
Deletions involving 4p16.3 due to different types of
rearrangements:
• Cytogenetically (microscopically) visible 4p deletion (~5060%)
p-arm
q-arm
deletion usually larger than 4 megabases (Mb)
Genetics of WHS
Deletions involving 4p16.3 due to different types of
rearrangements:
• Microdeletions (cannot be seen under the microscope)
detected by FISH using a probe for the WHS critical
region (red) (~25-30%)
4
deletion often
between 2-4 Mb
del(4)
WHS: cryptic deletions
Probe 190b4 (left) and probe 184d6 (right) deleted on
one chromosome 4. Both probes identify the WHS
critical region in 4p16.3
Wolf-Hirschhorn (4p-) Syndrome
• If needed, subtelomeric FISH screening
can be performed to determine if a
deletion is the result of an unbalanced
translocation
Wolf-Hirschhorn (4p-) Syndrome
• ~85% of patients have a “pure de novo deletion”
(85% of paternal origin)
• ~15% patients have: “ring 4” or “4p-mosaicism”,
or “der 4” due to an unbalanced translocation
(in 2/3 mother carries the rearrangement)
• Parents of WHS should have cytogenetic analysis
looking for a translocation or an inversion
Wolf-Hirschhorn (4p-) Syndrome
• If a parent is a balanced translocation carrier,
the risk to sibs of being affected with 4p
monosomy (WHS) or 4p trisomy is 
• The risk to the sibs of a proband is negligible
if the deletion in the proband is de novo
• Prenatal testing (CVS or amniocentesis) is
available if one parent is known to be a
carrier of a chromosome rearrangement
AR. with WHS at
age 11 months
Her boy-friend:
age 8 months
Wolf-Hirschhorn (4p-) Syndrome:
Three Important Challenges
• Feeding Difficulties
• Seizures
• Development Disability
Wolf-Hirschhorn (4p-) Syndrome
Feeding Difficulties:
• Central hypotonia  poor suck
• Oral facial clefts  difficulty in sucking
• Poorly coordinated swallow  aspirations
• G.E. reflux  irritability; recurrent RTI
• G.I. malformations – rare
Wolf-Hirschhorn (4p-) Syndrome
Feeding Difficulties:
Health Supervision
• Sustain weight gain and
health status  improvement of motor abilities
• Protect the airway
• Cope with G.E. reflux
• Referral to a dysphagia team 
- Swallowing studies in infancy + gastrostomy tube
Wolf-Hirschhorn (4p-) Syndrome
Feeding Difficulties
Treatment
• Increased caloric formulas and/or
oral/nasogastric tube feeding
• Standard therapy for G.E. reflux
- Nissen-Hill fundoplication
• Gastrostomy 40%
Wolf-Hirschhorn (4p-) Syndrome
Seizures
• Occurs in 90%
• Distinctive EEG abnormalities
Seizures In WHS
• Onset between 3 to 23 months of age, with a
peak incidence at around 9 to 10 months
• Unilateral clonic/tonic, with or without
secondary generalization
• Generalized tonic clonic
• On occasions lasting more than 15 minutes
• Often in clusters
Seizures In WHS
• Unilateral/generalized, clonic or tonic-clonic
status epilepticus: 60%
• Atypical absences (with a mild myoclonic
component), by 1 to 5 years of age: 60%
• Seizures stopped, by 2 to 13 years of age: 33%
• Off medication: 16%
Wolf-Hirschhorn (4p-) Syndrome
Seizures/Epilepsy
• A candidate gene for epilepsy was the GABAA
receptor gene. Maps proximal to the WHSCR
(4p12-p13).
• LETM1, a gene probably involved in Ca
signaling, flanking the WHSCR (and falling within
the newly proposed WHSCR-2), seems to be a
good candidate for seizures.
Wolf-Hirschhorn (4p-) Syndrome
Seizures/Epilepsy
Treatment
• Clonic/tonic-clonic seizures  valproate or phenobarbital
• Atypical absences  valproate  ethosuccimide 
benzodiazepines (carbamazepine worsens)
• Clonic/tonic-clonic or absence/myoclonic status
epilepticus  iv. Benzodiazepines
- Dr. Battaglia
Wolf-Hirschhorn (4p-) Syndrome
Developmental Disabilities
• Recent studies of large samples of individuals 
recognition of a more complete continuum of the
phenotype, pointing out a much wider clinical
spectrum than previously thought (Battaglia &
Carey, 2000; Battaglia et al., 2001, 2002)
Wolf-Hirschhorn(4p-) Syndrome
Developmental Disabilities
 Significant
65%
 Moderate
25%
 Mild
10%
Wolf-Hirschhorn (4P-) Syndrome
Developmental Disabilities
Findings
Expressive Language:
 Sounds / Words
 Simple Sentences
(6%)
Wolf-Hirschhorn (4P-) Syndrome
Developmental Disabilities
Findings
Comprehension:
 Limited/Contextual
Intention to communicate:
 Poor/Absent in early years
Wolf-Hirschhorn (4p-) Syndrome
Developmental Disabilities
Findings
• Sphincter control:
age 8-14 yr (day) 10%
• Walking unsupported:
age 2-7 yr
27%
• Walking with walker:
age 2-12 yr
18%
• Help dressing/undressing:
age 8-14 yr
18%
• Doing household tasks:
age 8-14 yr
18%
Wolf-Hirschhorn (4p-) Syndrome
Developmental Disabilities
Findings
Follow up (20 yr):
• Improvement of the motor abilities and of the disorder
of affect
• Improved adaptation to new situations; initial
differentiation of the “I” processes
• Improvement of the communicative abilities and of
the verbal comprehension with extension of the
gesture repertoire
• Reduction of isolation and anxiety
Wolf-Hirschhorn (4p-) Syndrome
Developmental Disabilities
Health Supervision
• Absent/poor speech  speech evaluation
• DD  psychometric evaluation
• Impaired motoric aspects  motoric evaluation
Wolf-Hirschhorn (4p-) Syndrome
Developmental Disabilities
Health Supervision & Treatment
• Referral to early intervention programs.
• Enrollment in an individualized rehabilitation program
that covers motor aspects (including oral motor and
feeding therapy), cognition, communication, and
socialization.
• Appropriate school placement after full evaluation
• Planning for transition to adulthood (vocational
training, living situation) to begin in adolescence.
Wolf-Hirschhorn (4p-) Syndrome
Other Clinical Findings
• Heart anomalies: Not complex; amenable to repair
• Genitourinary: Variety of structural defects (high
degree of vesicoureteric reflux) – watch for
• Eye: Coloboma, glaucoma, ptosis
Wolf-Hirschhorn (4p-) Syndrome
Other Clinical Findings
• Dental: Altered tooth development
• Skeletal: Medically significant malformations to
minor anomalies of limbs and skeleton; scoliosis
Wolf-Hirschhorn (4p-) Syndrome
Health Supervision
• Heart auscultation/EKG/echocardiography in
infancy
• Renal function/renal ultrasound testing in
infancy and later
• Ophthalmology consultation in infancy
• Otolaryngological evaluation and audiological
screening mandatory in infancy/childhood
Wolf-Hirschhorn (4p-) Syndrome
Health Supervision
• Orthodontic evaluation in children/adolescents
• Club feet: early referral for evaluation/treatment
• Scoliosis/kyphosis: routine check
Wolf-Hirschhorn (4p-) Syndrome
The right and the need of each patient
with WHS to receive not just the
ordinary care given to any child but also
the extraordinary care necessary for
coping with the problems of the del(4p)
disorder.
Battaglia A, Carey JC, Wright TJ
Wolf-Hirschhorn Syndrome
(Updated June 2006)
In: GeneReviews: Genetic Disease Online Reviews at
GeneTests-GeneClinics [database online].
Copyright, University of Washington, Seattle. Available at
http://www.geneclinics.org
Battaglia, A.
Wolf-Hirschhorn (4p-) Syndrome
in
Management of Genetic Syndromes, 2nd Edition
Cassidy SB, Allanson JE (eds)
Wiley Publishers, New York, NY, 2004.
Wolf-Hirschhorn (4p-) Syndrome:
Molecular Genetic Pathogenesis
• Over the last 10 years the WHSCR (the minimal
deleted region) has been reduced to 165 kb
(Wright et al., 1997). It contains two important
genes of unknown function, WHSC1 and WHSC2
(Wright et al., 1997; Stec et al., 1998).
• Several candidate genes, including FGFR3,
MSX1, and LETM1, fall in the flanking regions.
These genes are deleted in most patients and may
play a role in some aspects of the phenotype.
Wolf-Hirschhorn (4p-) Syndrome
Molecular Genetic Pathogenesis
• More recently, Endele et al., (2003) and
Winterpacht et al., (2003) identified three
novel genes (WHSC3, WHSC4, WHSC5) in
the critical region
Wolf-Hirschhorn (4p-) Syndrome
Molecular Genetic Pathogenesis
• A new WHSCR-2, contiguous distally to the
currently defined critical region, has recently
been proposed (Zollino et al., 2003)
• DFNA6, one of the>25 genes responsible
for nshl has been mapped to 4p16.3snhd
in 15% WHS
Genetics of WHS
Deletions involving 4p16.3 due to different types of
rearrangements:
• Unbalanced translocation either new or from a parental balanced
translocation (~15-25%)
possible parental chromosomes:
balanced
affected offspring: both a deletion of some
gray chromosome and a duplication of
some red chromosome
these rearrangements may be too small to see cytogenetically (cryptic)
CGH microarray is superior in characterizing
many cryptic abnormalities
Previous
karyotype
41 46,XY
5
4
Previous FISH
Deleted for
WHS probe;
Subtelomere
FISH panel: 4p
deleted and
replaced with
7p
Current array CGH
results
4p deletion
3.5-4.5 Mb
7p
duplication
6-7 Mb
Comparison
CGH microarray identified
same abnormalities as
FISH, but also gave
approximate sizes of the
deletion and the
duplication
Additional Examples
Cytogenetic Finding CGH Microarray Result
46,XX
4p deletion and 11p
duplication
46,XX
4p deletion and 8p
duplication
46,XX,del(4p)
4p deletion and 11p
duplication
46,XX,inv(4p)
4p deletion and 8p
duplication
Limitations of CGH microarray
• Will only detect the gain or loss of genomic material
that is represented on the slide
• No slide is yet clinically available that represents
the entire human genome (currently can still miss
very small imbalances)
• Repetitive regions of the human genome are
cannot be analyzed using this technology
Chromosome ends with repetitive
DNA – the acrocentrics
Both the stalk and the
satellite region contain
only repetitive DNA and
are not represented on
CGH microarray slides
CGH micoarray does NOT identify unbalanced
translocations involving acrocentric p-arms
Previous
karyotype
6 4p deleted
3 and
6 replaced
with
unknown
material
Previous
FISH
Chromosome 4
image
Deleted for
WHS
critical
region
CGH microarray
FISH with chromosome
15p probe
Only detected a
4p deletion
15p probe in green
der(4)
15
15
4
2 other patients in this group also had unbalanced translocations
involving an acrocentric p-arm only detected using a combination of
regular cytogenetic studies (microscope) and FISH with probes specific
to the acrocentric p-arms
Patients with an unbalanced translocation often
present with an exception to some expected clinical
manifestations
• Microcephaly
– Previous reports: present in almost all patients
(Estabrooks et. al, 1995; Zollino et. al, 2000; Buggenhout et.
al, 2004)
– 3/16 did not have microcephaly– all had a cryptic
deletion of 4p and duplication of 11p
Patients with an unbalanced translocation often
present with an exception to some expected clinical
manifestations
• Hypospadias
– Previous report: greater than 4.4 Mb deletion (Zollino et. al, 2000)
– 7/9 males in our study had hypospadias
– 4/7 less than 4.4 Mb deletion and all had unbalanced
translocations
•
•
•
•
4p deletion; 15p duplication
4p deletion; 14p or 22p duplication
4p deletion; 11p duplication (cryptic)
4p deletion; 7p duplication (cryptic)
Patients with an unbalanced translocation often
present with an exception to some expected clinical
manifestations
• Hearing loss
– Previous report: greater than ~6 Mb deletion (Estabrooks et. al,
1995)
– 9/25 patients in our study had hearing loss
– 3/9 less than 6 Mb deletion
2/3 had unbalanced translocations
• 4p deletion; 11p duplication (cryptic)
• 4p deletion; 7p duplication (cryptic)
Patients with an unbalanced translocation often
present with an exception to some expected
clinical manifestations
• Heart Defects
– Previous report: greater than ~6.0 Mb deletion (Zollino et. al, 2000)
– 10/25 patients in our study had heart defects
– 3/10 less than 6.0 Mb deletion
2/3 unbalanced translocation
• 4p deletion; 7p duplication (cryptic)
• 4p deletion; 8p duplication (cryptic)
Conclusions
• CGH microarray successfully detected a deletion of 4p in
each patient previously diagnosed with a 4p deletion (26/26).
• In a subset of patients (5/26), CGH microarray also detected
an additional duplication of another region not detected by a
microscopic chromosome analysis plus WHS critical FISH.
• Subtelomeric FISH analysis was also able to detect these
additional duplications; however, CGH microarray analysis
was also able to characterize the size of the regions of
deletion and duplication.
Conclusions
• CGH microarray analysis does not identify duplications of the
acrocentric p-arms
• CGH microarray should be used in conjunction with a regular
karyotype analysis for optimal characterization of the genetic
imbalance.
• De novo inheritance (new mutation) should not be presumed.
Parental studies using the technology necessary to confirm
the deletion in the child should be pursued to determine
recurrence risk.
– If deletion is cytogenetically visible in child, and did not require a FISH
confirmation, traditional cytogenetic analysis is sufficient for parental
studies.
– If FISH was required for diagnosis of the child, parents should be
studied by FISH with WHS critical region probe to rule out a cryptic
balanced translocation in either parent.
Conclusions
• Unbalanced translocations were more common
than previously expected (42.3% (11/26) vs 1525% respectively).
• Patients with an unbalanced translocation often
confound some of the expected clinical
manifestations.
Acknowledgements
• Primary Children’s Medical Center Foundation
• Children’s Health Research Center
• Patients with WHS, their families, and
caregivers
• 4p- Support Group
• University of Utah Cytogenetics Laboratory