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alexander disease ( ad ) is a fatal and progressive leukodystrophy of the central nervous system .
the destruction of white matter in a rostrocaudal gradient is accompanied by the accumulation of abnormal deposits , known as rosenthal fibers ( rfs ) , in astrocytes , which result in cell death .
the clinical phenotype of ad has been divided into three types based on age at onset , i.e. , infantile , juvenile , and adult ad . however , clinically the disease is highly variable among patients in the same disease group .
typical features of the infantile form occur before 2 yr old , and present as progressive macrocephaly , developmental delay , spasticity , and seizures .
seizure is a common clinical symptom in ad , but infantile spasms are a less well - known manifestation .
brain magnetic resonance imaging ( mri ) reveals predominantly frontal white matter involvement of low signal intensity on t1-weighted images and high signal intensity on t2-weighted images . since brenner et al .
( 1 ) discovered a missense mutation in glial fibrillary acidic protein ( gfap ) gene in chromosome 17th in ad , dna analysis has proven to be a valuable diagnostic modality .
it persisted for 30 min , and his parents observed upward eyeball fixation and tonicclonic movement of the extremities .
however , treatment was not sought at the time . at his home on the day of this hospitalization , a seizure redeveloped , persisted for about an hour and then spontaneously stopped .
his parents then brought the patient to our emergency room where the seizure was observed by doctors .
pupils were fixed without deviation with nictitating of eyelids , lip smacking , and stiffness of the right extremities .
the patient had no relevant birth or family history . at the time of hospitalization , his body temperature was 36.6 , pulse rate 128/min , and respiratory rate 28/min . in terms of body measurements ,
his body weight was 8.8 kg ( 20th percentile ) , height 75 cm ( 90th percentile ) , and head circumference 51 cm ( more than the 97th percentile ) .
anterior fontanel was soft and flat , and he had macrocephaly and a projecting forehead , similar to that observed in hydrocephalus .
he was unable to control his head , and his language and social skills were at the 1 - 2 month post - natal level .
the complete blood count was within normal limits , and total protein / albumin was 6.2/4.3 g / dl , na / k / cl 138/4.9/104
meq / l , blood sugar 100 mg / dl , bun / cr 11/0.4 mg / dl , and ast / alt 26/22
normal finding was seen by 7.93 ( 4.9 - 20.5 mm / m creatinine ) in n - acetylaspartic acid ( naa ) of urine .
brain mri showed an absence of myelination except in the frontal lobe and in a portion of the temporal lobe ( fig .
dna analysis revealed that the 716th base sequence of the 4th exon of the gfap gene showed thymine substituted for guanine ( c.716g > t ) , which led to r239l missense mutation at the 239th amino acid involving the replace of arginine by leucine .
additionally , when we examined the dna of his parents and older sister , it appeared that they had a normal base sequence ( fig .
interictal waking electroencephalography ( eeg ) showed slow waves in the frontal lobe , but no epileptic discharge ( fig .
three months later , at the age of 11 months , infantile spasms of the flexor type developed accompanied with vocalization after waking up .
the spasms came under control after starting vigabatrin ( 40 mg / kg / day ) and after the third day of this medication , no more spasm was observed .
a follow - up mri at 24 months of age showed disease progression ( fig .
1c , d ) , he is in good nutritional condition and has a relatively good cardiopulmonary function .
however , he suffers from intermittent vomiting , dysphagia , irritability , easy startling , developmental retardation , slow progressive spasticity of the extremities , and seizures .
w. stewart alexander , in his original description of a case in 1949 ( 2 ) , reported a boy with a rapidly enlarging head , hydrocephalus , and developmental delay who died at 15 months of age following an 8-month illness .
ad is a progressive and usually fatal neurological disorder in which the destruction of white matter in the brain ( 3 , 4 ) .
however , little information is available on the pathogenesis of ad , or on how the gfap mutation leads to leukodystrophy ( 5 , 6 ) . in 1976
, russo et al . ( 7 ) suggested that ad could be divided into three age - dependent clinical subgroups : infantile , juvenile , and adult and most authors have adopted this classification .
the infantile form of ad is most common ( 8 - 11 ) , and usually becomes apparent during the first two years of life .
typically patients show both mental and physical developmental delays , followed by loss of milestones , an abnormal increase in head size , and often seizures .
the average age of onset is 6 months and the average age of survival after diagnosis is 2 yr and 4 months . but
wakabayashi et al . ( 12 ) reported a japanese case of infantile ad who survived at the age of 25 yr and 7 months .
thus , the clinical progress in ad may be varied by case . in our patient , although seizure occurred at age 8 months , we suggest that clinical manifestations had developed before at least age 3 months because he was unable to control his head at age 4 months .
( 13 ) , seizures often appear at an early stage , whereas spastic quadriparesis is less prominent and occurs later .
our patient showed prominent macrocephaly , and developmental retardation before the seizure attacks which occurred at age 8 months .
we initially observed slow waves on the frontal area on interictal sleep eeg , but there was no epileptic discharge ( fig .
three months later , at age 11 months , infantile spasms developed after waking up .
infantile spasms in ad cases are a remarkable presentation , and are rare according to many reports . although gingold et al . ( 14 ) described briefly that his ad patient developed multifocal seizures at age 11 months and eeg demonstrated hypsarrhythmia , which was recorded at the left posterior hemisphere during an ictal episode , no further description was provided .
they first described an ad case accompanied by infantile spasms , and since no further cases have been published , our case is the second , which is why we consider this case valuable .
we controlled these infantile spasms with vigabatrin , which has a highly effective anticonvulsant action .
a definitive diagnosis was only possible by pathological examination of brain tissue , obtained either at biopsy or autopsy , for rfs until the genetic diagnostic method became available .
biochemical studies on compositions of rfs revealed that a large portion of the fibers consisted of the heat shock protein , b - crystallin ( 15 ) , and lesser amounts of heat shock protein 27 and ubiquitin ( 16 ) .
, brain white matter degeneration appears remarkably in the frontal lobe on mri and hydrocephalus occurs infrequently ( 17 , 18 ) .
gfap was found to be distributed much more on astroglial cell channels comprised of intermediate filaments of diameter 7 - 11 nm and codes by gene 17q21 's gfap gene .
ad can now be diagnosed in a high percentage of cases by analyzing dna obtained from peripheral blood , which obviates the need for brain biopsy .
brenner et al . ( 1 ) sequenced the gfap coding region in the dna from 11 unrelated patients who had died of ad and discovered that 10 patients had mutations in the gfap coding region .
li et al . ( 19 ) analyzed the dna of 44 ad cases and found a gfap gene mutation in 41 cases .
moreover , as studied parental dnas have also failed to reveal such mutations , it must be presumed that they are wholly spontaneous in nature .
this indicates that ad is not autosomal recessive , as had previously been thought by wohlwill et al .
( 21 ) , but that it is possibility due to a gonadal mosaicism . in our patient , the r239l gfap gene mutation ( fig .
3 ) in which 716th base sequence of 4th exon showed a guanine to thymine substitution ( c.716g > t ) , and as a result , the 239th amino acid of gfap is changed from arginine to leucine .
this was determined by conducting direct base sequence analysis after amplifying all exons and intron regions of the gfap gene by pcr from peripheral blood genomic dna . however , the patient 's parents and older sister had a normal base sequence .
in addition , the position of the gfap gene mutation in ad which found up - to - date differs from this case . therefore , the r239l gfap gene mutation in the present case is presumed to be a de novo mutation or gonadal mosaicism . in conclusion
, the authors report a rare case of ad accompanied by infantile spasms that was diagnosed by gfap gene analysis in an 8-month - old male with seizures , psychomotor developmental retardation , macrocephaly , and spasticity of the extremities .
alexander disease ( ad ) is a rare leukodystrophy of the central nervous system of unknown etiology . 
 ad is characterized by progressive failure of central myelination and the accumulation of rosenthal fibers in astrocytes , and is inevitably lethal in nature . 
 symptomatically , ad is associated with leukoencephalopathy with macrocephaly , seizures , and psychomotor retardation in infants , and usually leads to death within the first decade . 
 its characteristic magnetic resonance imaging ( mri ) findings have been described as demyelination predominantly in the frontal lobe . moreover , 
 dominant mutations in the gfap gene , coding for glial fibrillary acidic protein ( gfap ) , a principal astrocytic intermediate filament protein , have been shown to lead to ad . 
 the disease can now be detected by genetic diagnosis . 
 we report the korean case of an 8-month - old male patient with ad . 
 he was clinically characterized due to the presence of psychomotor retardation , megalencephaly , spasticity , and recurrent seizures including infantile spasms which is a remarkable presentation . 
 demyelination in the frontal lobe and in a portion of the temporal lobe was demonstrated by brain mri . 
 moreover , dna analysis of peripheral blood showed the presence of a r239l mutation in the gfap gene , involving the replacement of guanine with thymine .