Prenatal clinical manifestations in individuals with COL4A1/2 variants.

BACKGROUND: Variants in the type IV collagen gene (COL4A1/2) cause early-onset cerebrovascular diseases. Most individuals are diagnosed postnatally, and the prenatal features of individuals with COL4A1/2 variants remain unclear. METHODS: We examined COL4A1/2 in 218 individuals with suspected COL4A1/2-related brain defects. Among those arising from COL4A1/2 variants, we focused on individuals showing prenatal abnormal ultrasound findings and validated their prenatal and postnatal clinical features in detail. RESULTS: Pathogenic COL4A1/2 variants were detected in 56 individuals (n=56/218, 25.7%) showing porencephaly (n=29), schizencephaly (n=12) and others (n=15). Thirty-four variants occurred de novo (n=34/56, 60.7%). Foetal information was available in 47 of 56 individuals, 32 of whom (n=32/47, 68.1%) had one or more foetal abnormalities. The median gestational age at the detection of initial prenatal abnormal features was 31 weeks of gestation. Only 14 individuals had specific prenatal findings that were strongly suggestive of features associated with COL4A1/2 variants. Foetal ventriculomegaly was the most common initial feature (n=20/32, 62.5%). Posterior fossa abnormalities, including Dandy-Walker malformation, were observed prenatally in four individuals. Regarding extrabrain features, foetal growth restriction was present in 16 individuals, including eight individuals with comorbid ventriculomegaly. CONCLUSIONS: Prenatal observation of ventriculomegaly with comorbid foetal growth restriction should prompt a thorough ultrasound examination and COL4A1/2 gene testing should be considered when pathogenic variants are strongly suspected.

Homozygous ADCY5 mutation causes early-onset movement disorder with severe intellectual disability.

BACKGROUND: Mutations of theADCY5 have been identified in patients with familial dyskinesia, early-onsetautosomal dominant chorea and dystonia, and benign hereditary chorea. Most ofthe ADCY5 mutations are de novo or transmitted in an autosomal dominantfashion. Only two pedigrees are known to show autosomal recessive inheritance. OBJECTIVES: We report twosiblings with severe ID, dystonic movement, and growth failure with unknownetiology. METHODS: We planned a proband-parentapproach using whole exome sequencing. RESULTS: Homozygous mutationin exon 21 of the ADCY5 (p.R1238W) was identified in the siblings. Althoughtheir parents were heterozygous for the mutation, they were free from clinicalmanifestations. CONCLUSIONS: Our results furtherexpand the phenotype/genotype correlations of the ADCY5-related disorders.Mutations of ADCY5 should be considered in pediatric patients with ID andinvoluntary movement.

De novo missense mutations in NALCN cause developmental and intellectual impairment with hypotonia.

Three recessive mutations in the sodium leak channel, nonselective (NALCN) have been reported to cause intellectual disability and hypotonia. In addition, 14 de novo heterozygous mutations have been identified in 15 patients with arthrogryposis and neurodevelopmental impairment. Here, we report three patients with neurodevelopmental disease and hypotonia, harboring one recurrent (p.R1181Q) and two novel mutations (p.L312V and p.V1020F) occurring de novo in NALCN. Mutation p.L312 is located in the pore forming S6 region of domain I and p.V1020F in the S5 region of domain III. Mutation p.R1181Q is in a linker region. Mapping these three mutations to a model of NALCN showed p.Leu312 and p.Val1020 positioned in the hydrophobic core of the pore modules, indicating these two mutations may affect the gating function of NALCN. Although p.R1181Q is unlikely to affect the ion channel structure, previous studies have shown that an analogous mutation in Caenorhabditis elegans produced a phenotype with a coiling locomotion, suggesting that p.R1181Q could also affect NALCN function. Our three patients showed profound intellectual disability and growth delay, facial dysmorphologies and hypotonia. The present data support previous work suggesting heterozygous NALCN mutations lead to syndromic neurodevelopmental impairment.

[Long-term outcome of childhood hypoxic-ischemic encephalopathy].

OBJECTIVE: To propose an adequate rehabilitation program for children suffering from hypoxic-ischemic encephalopathy (HIE) based on estimated outcomes. METHODS: Participants were 42 children, 28 boys and 14 girls, who suffered from HIE after neonatal period. We divided them into three groups; favorable (GMFCS level 1 or 2), moderate (level 3 or 4), and unfavorable (level 5), and compared the extent of brain lesions on MRI, age of onset, and complications among the groups. RESULTS: The number of children in favorable, moderate, and unfavorable groups was 10, 10 and 22, respectively. All children in favorable and moderate groups showed focal cerebral lesions on MRI. In contrast, most children in unfavorable group (19/22) had diffuse brain damage and the rest were infantile onset with focal cerebral lesions. The etiology and situation of HIE did not differ among three groups. Three children in moderate group whose onsets were earlier than 5 months showed lesions similar to those in neonatal HIE; in bilateral basal ganglia, thalamus, and perirolandic cortex. In favorable group, 7 children were able to walk independently within 5 months after the insult, but 9 had moderate or severe mental retardation and 3 showed severe visual impairment. A majority of unfavorable group developed scoliosis or hip dislocation, and underwent tracheostomy or gastrostomy. Five children who had stayed acute hospitals for longer than 6 months developed irreversible complications such as joint contractures before discharge. CONCLUSIONS: Children with focal cerebral lesions need continual rehabilitation and education for mental retardation and visual impairment, even if they can walk within several months after HIE. Those with diffuse brain damage need sufficient rehabilitation as early as possible to avoid developing secondary complications. MR image, age of onset, and clinical course were of great prognostic value to make appropriate long-term rehabilitation and education programs.

Cross-cultural adaptation, validity and reliability of the Japanese version of ABILHAND-kids for children with cerebral palsy using Rasch measurement model.

PURPOSE: The aim of this study was to develop the Japanese version of the ABILHAND-Kids and to examine its psychometric properties for Japanese children with cerebral palsy (CP). METHODS: The experimental version of 75 items was developed using forward-backward translation method. Parents of 137 children with CP answered it. Their responses were analyzed to successive items, and psychometric properties of the final version were investigated through the Rasch measurement model. RESULTS: The Japanese version of the ABILHAND-Kids contained 22 items. It showed valid item-patient targeting, no significant floor and ceiling effects, and no differential item functioning for demographic and clinical subgroups. All items contributed to the definition of one-dimensional measure. For internal consistency, the person separation index was 0.94. For test-retest reliability, the intraclass correlation coefficients were 0.96 (95% CI: 0.92-0.98). The minimal detectable difference was calculated with a logit score of 0.79 and a total raw score of 4.50. The logit score showed a strong correlation with the Manual Ability Classification System level (ρ= -0.70) and the Gross Motor Function Classification System level (ρ= -0.62). CONCLUSIONS: The Japanese version of the ABILHAND-Kids was found to be valid and reliable. It appears to be a good tool for assessing manual abilities in daily activities in children with CP.

Impairment of upper limb function affects participation and quality of life in children with cerebral palsy, and adequate assessment tools are essential to appropriate planning and evaluation of interventions.The Japanese version of the ABILHAND-Kids is a valid and reliable measure of manual ability in children with cerebral palsy.The Japan-specific items and calibrations allows for evaluation that takes Japanese culture into consideration.

[Cyclophosphamide pulse therapy effective for childhood-onset refractory multiple sclerosis: a case report].

We report a case of a 15-year-old girl with relapsing-remitting multiple sclerosis (MS) who received cyclophosphamide pulse therapy. At the age of 5 years, she displayed symptoms such as headache and unconsciousness after varicella infection as the first episode of MS. She had been treated with methylprednisolone pulse therapy, intravenous immunoglobulin, interferon-beta1b, and azathioprine. However, she had relapsed 12 times by the age of 15 years. At this time, she showed weakness and severe paralysis of her left leg, and even 1 month after methylprednisolone pulse therapy, she still had gait impairment and showed gadolinium-enhanced lesion on brain magnetic resonance imaging. We then started cyclophosphamide pulse therapy (600 mg/m2) once a month for 12 months combined with interferon-beta1a. She had no serious side effects and she could walk again after 4 months on cyclophosphamide treatment. She has been free from relapse for 2 years and 8 months until the present time. Although only a few studies have indicated the efficacy of cyclophosphamide pulse therapy for childhood MS, we consider careful use of cyclophosphamide could be one of the options for refractory childhood MS.

Childhood-onset epilepsy in patients with dyskinetic cerebral palsy caused by basal ganglia and thalamic lesions.

OBJECTIVE: To elucidate the incidence and outcomes of childhood-onset epilepsy and associated factors in term-born patients with basal ganglia and thalamic lesion (BGTL)-induced dyskinetic cerebral palsy (DCP) caused by perinatal hypoxic-ischemic encephalopathy (HIE). METHODS: We studied 104 term-born patients with BGTL-induced DCP (63 males and 41 females, aged 2-22 years) to investigate the incidence of epilepsy and the factors related to its development. We used multivariate analysis to assess perinatal factors, gross motor function, and the extent of brain lesions. We also investigated the seizure onset, clinical course, and electroencephalography (EEG) characteristics. RESULTS: The cumulative epilepsy incidence was 36%. Multiple logistic regression analysis revealed that deep white matter lesions were the only independent risk factor for epilepsy. The confirmed seizure types included epileptic spasms (ES, n = 13), myoclonic seizures (MS, n = 6), and focal-onset seizures (FS, n = 24). Only patients with deep white matter lesions exhibited ES or MS. The symptoms of FS resembled those of self-limited epilepsy with centrotemporal spikes; however, only half of the patients reached remission by the time of investigation, and four patients had more than one seizure per month despite appropriate drug therapy. Focal spikes in the peri-rolandic area were detected not only in patients with FS but also in half of the patients without epilepsy. CONCLUSIONS: One-third of term-born patients with BGTL-induced DCP caused by perinatal HIE develop epilepsy, and deep white matter lesions increase the likelihood of epilepsy. Preparation for early-onset ES, MS, and subsequent FS is beneficial.

[Effects of botulinum toxin therapy for respiratory distress in patients with cervical hypertonia].

Botulinum toxin A (BTX-A) therapy has been approved as a first-line therapy for spastic torticollis. However it has been suggested as that its use in patients with respiratory distress should be decided cautiously. We treated 5 patients with abnormal posture, cervical hypertonia and obstructive respiratory distress by BTX-A, and analyzed its efficacy for respiratory distress by their Tsui score and respiratory status after BTX-A therapy. All 5 patients clinically had some degree of dysphagia before BTX-A therapy. Cervical hypertonia and induced abnormal posture were improved in all patients. The youngest patient could control muscle tone after only 2 doses of BTX-A and subsequently maintained a good condition without additional BTX-A. BTX-A therapy can decrease torsion and hyperextension of the upper respiratory tract by reducing cervical hypertonia. Consequently, it may improve respiratory status. On the other hand, mild dysphagia and excessive salivation was noted in one patient for each symptom. It is safe to avoid BTX-A invasion to the anterior muscle of neck and rapid changes in the swallowing pattern.

Risk factors for hip dislocation in dyskinetic cerebral palsy.

PURPOSE: To investigate the risk factors for hip displacement in patients with dyskinetic cerebral palsy (DCP). METHODS: We evaluated 81 patients with DCP, 45 males and 36 females, aged 10-22 years, risk factors for hip displacement were evaluated using multivariate logistic regression analysis with primary brain lesions, Gross Motor Function Classification System (GMFCS) level, gestational age, birth weight, Cobb's angle, and complication of epilepsy as independent factors. Hip displacement was defined as migration percentage >30%. Primary brain lesions were classified into globus pallidus (GP), thalamus and putamen (TP), and others using brain magnetic resonance imaging (MRI). Perinatal and clinical features were compared between patients with GP lesions and those with TP lesions. RESULTS: Hip displacement was observed in 53 patients (67%). Higher GMFCS levels (p = 0.013, odds ratio [OR] 2.6) and the presence of GP lesions (p = 0.04, OR 16.5) were independent risk factors for hip displacement. Patients with GP lesions showed significantly higher GMFCS levels, more frequent hip displacement, and lower gestational age and birth weight than those with TP lesions. CONCLUSION: Primary brain lesion location may be an important factor in predicting hip displacement among patients with DCP. Appropriate risk assessment using brain MRI may contribute to the early detection and intervention of hip displacement because brain lesion location can be assessed during infancy before GMFCS level is decided.

Functional outcomes of children with dyskinetic cerebral palsy depend on etiology and gestational age.

OBJECTIVE: To elucidate the differences in etiology of dyskinetic cerebral palsy (DCP) between term-born and preterm-born children and its relationship to functional outcomes. METHODS: We determined the etiology of DCP based on the clinical course and brain MRI of 163 term-born and 136 preterm-born children. Information about genetic abnormality was also collected if available. Functional outcomes were compared between the two major etiologies in each group, i.e., hypoxic ischemic encephalopathy (HIE) and bilirubin encephalopathy (BE), using four standardized classification systems, i.e., Gross Motor Function Classification System (GMFCS), Manual Ability Classification System (MACS), Communication Function Classification System (CFCS), and Eating and Drinking Ability Classification System (EDACS). RESULTS: The most common etiologies were HIE (123/163) in term-born and BE (93/136) in preterm-born children. Genetic mutations were identified in 14 of 30 term-born children with no other known etiology. GMFCS levels of the preterm children with BE were significantly poorer than those of term children with HIE (p < 0.01). Both the CFCS and EDACS levels were significantly better in preterm children with BE than in term children with HIE (p < 0.01). CONCLUSION: The most common etiology of DCP is different between term-born and preterm-born children, and the distribution of functional impairment is significantly influenced by etiology and gestational age. The difference should be taken into consideration to allow the provision of adequate interventions.

Magnetic Resonance Imaging Findings in Preterm Infants With Bilirubin Encephalopathy Beyond Three Years Corrected Age.

BACKGROUND: Magnetic resonance imaging (MRI) abnormalities in preterm infants with bilirubin encephalopathy (BE) become less clear as the infants age. We assessed MRI findings in children with preterm BE older than 36 months corrected age (CA). METHODS: In a previous questionnaire survey, hospitals were asked to provide head MRI data of patients older than 36 months CA. MRI findings were reviewed by three pediatric neurology specialists and classified as no abnormalities, partial globus pallidus (GP) lesions, or diffuse GP lesions. RESULTS: In total, 33 MRI scans were available from 28 patients. The median gestational age and birth weight were 26 weeks and 824 g, respectively. The prevalence of MRI abnormalities was 100% in patients at 37 to 48 months CA, 71% in those at 49 to 60 months CA, 50% in those at 61 to 72 months CA, 67% in those at 73 to 84 months CA, and 38% in those at 85 months CA or older. Partial GP lesions were more common than diffuse GP lesions at all ages. No significant differences in sex, gestational age, birth weight, or gross motor function impairment were observed among lesion groups. CONCLUSIONS: GP lesions were detected on MRI in most children with preterm BE when studied after 36 months CA, although MRI abnormalities became less apparent along with age. Partial GP lesions may be a characteristic of older children with preterm BE.

Auditory brainstem response in preterm infants with bilirubin encephalopathy.

AIM: To clarify auditory brainstem response (ABR) in preterm infants with bilirubin encephalopathy and the relationships between ABR and clinical variables. METHOD: We retrospectively reviewed the ABR waveforms of 56 preterm infants with BE and graded them as "no response", "abnormal interwave separation", or "normal". Patient backgrounds, the peak total bilirubin level, the bilirubin/albumin ratio, verbal communication ability, and newborn hearing screening test results from an automated ABR evaluation had been collected during an earlier nationwide survey. RESULTS: The frequency of abnormal ABR findings decreased with age. Verbal communication tended to be poorer in patients with more severe ABR abnormalities. ABR findings improved in 7 of 29 infants with available serial ABR data. Both gestational age and the peak total bilirubin level were relatively lower in patients with than in those without improved ABR findings. Newborn hearing screening using automated ABR evaluation yielded data consistent with manual ABR findings in 16 of 20 patients who underwent both examinations. CONCLUSIONS: ABR abnormalities in preterm infants with bilirubin encephalopathy may improve over time, especially in those with a lower gestational age and peak total bilirubin level. Newborn hearing screening using automated ABR may fail to detect abnormalities in some infants.

Diagnosis of Bilirubin Encephalopathy in Preterm Infants with Dyskinetic Cerebral Palsy.

INTRODUCTION: Very preterm infants are susceptible to bilirubin neurotoxicity, the signs of which are unclear during early infancy. We investigated children born preterm and later diagnosed with bilirubin encephalopathy (BE) to gain insights into accurate early diagnosis. METHODS: We identified 93 children born preterm and clinically diagnosed with BE who visited our hospital between 2006 and 2018. Perinatal history, findings of auditory brainstem response (ABR), brain magnetic resonance imaging (MRI), and functional outcomes were investigated retrospectively based on chart review. RESULTS: The mean gestational age and birth weights were 27.2 weeks and 991 g, respectively. During the neonatal period, only 3% (2/71) had exchange transfusions, and none were diagnosed with acute BE. ABR was abnormal in 64% (51/80), but the majority (34/51) required no hearing aids. Brain MRI taken between 6 and 18 months of age revealed bilateral T2 hyperintensity of the globi pallidi in 91% (60/66); subsequently, the rate decreased with age. Functional communication outcomes were markedly superior to gross motor and hand function outcomes. CONCLUSION: For early diagnosis of BE, brain MRI is recommended at a corrected age of between 6 and 18 months, especially for those with abnormal ABR during early infancy, and even with no apparent history of marked neonatal hyperbilirubinemia.

A questionnaire survey on the efficacy of various treatments for dyskinetic cerebral palsy due to preterm bilirubin encephalopathy.

OBJECTIVES: Preterm children with severe dyskinetic cerebral palsy due to bilirubin encephalopathy often suffer from marked generalised hypertonus as they age. We performed a questionnaire survey to investigate patient-reported outcomes of treatments for improving their activities of daily life. METHODS: A mail questionnaire was administered to the caregivers of 67 children with preterm bilirubin encephalopathy aged >4 years. We asked about the type of treatments they received and their efficacy using a five-point subjective scale for the following five domains: motor function, postural stability, sleep, pain, and care burden. The names of oral drugs and their efficacies were also explored. RESULTS: The response rate of the questionnaires was 62.7% (42/67), and we analysed the results from 41 validated cases. All children underwent rehabilitation. A total of 30 children received oral drugs, 22 botulinum toxin, 12 orthopaedic surgery, and 3 intrathecal baclofen. Each of these treatments was subjectively reported to be effective in more than half of the recipients for each of the five domains, whereas 23 (56%) required more than two types of treatments other than rehabilitation. Chlordiazepoxide was the most commonly used oral drug, by 28 children (68%), and was discontinued in 7 patients (25%) only. In the sleep domain, the rate of a positive effect was significantly higher for oral drugs (92.7%) than the other treatments (p < 0.01). CONCLUSION: All treatments were partially effective, but their appropriate combination based on a multidisciplinary approach is essential for muscle tone management in children with preterm bilirubin encephalopathy.

Outcome of hemiplegic cerebral palsy born at term depends on its etiology.

OBJECTIVES: To elucidate the etiology and its relationship to the outcomes of hemiplegic cerebral palsy (HCP). PARTICIPANTS AND METHODS: MR images and outcomes of 156 children with HCP born at term and older than three years were investigated in two major centers for cerebral palsy in Japan. Etiologies were classified into perinatal ischemic stroke (PIS), cerebral dysgenesis (CD), and others. PIS was divided into periventricular venous infarction (PVI) and two types of arterial infarction; middle cerebral artery infarction (MCAI) and deep gray matter infarction (DGMI). Initial signs and the time of presentation were investigated among the three types of PIS. As functional outcomes, laterality of paresis, age at initial walk, affected hand's function, intellectual development, and occurrence of epilepsy were compared among all the four types. ETIOLOGY: PIS was found in 106 children (68%), while CD accounted for 28 (18%). Among PIS, venous infarction was more common than arterial infarction (62:44). OUTCOMES: PVI revealed later presentation of motor asymmetry and more involvement of lower extremity as the initial sign among PIS groups. Only MCAI showed right-side predominance in laterality of paresis. DGMI related to better intellectual development and PVI showed lower occurrence of epilepsy, while there was no significant difference in affected hand's function among the four groups. PIS groups showed significantly earlier attainment of independent walk, better intellectual development, and lower occurrence of epilepsy than CD. CONCLUSIONS: PVI was the most common cause of HCP born at term, and the etiology closely related to the initial signs of hemiplegia and overall outcomes.

[Suspected case of pseudohypoparathyroidism type II].

We experienced a suspected case of pseudohypoparathyroidism type II. The patient came to our emergency room with no thermal convulsion. The Ellsworth-Howard test was applied to the patient to determine the type of PHP.

Cerebellar injury in preterm children with cerebral palsy after intraventricular hemorrhage: Prevalence and relationship to functional outcomes.

OBJECTIVES: To elucidate the prevalence of cerebellar injury and its relationship to functional outcomes in preterm children with cerebral palsy (CP) after intraventricular hemorrhage (IVH). PARTICIPANTS: We selected 69 children (40 males and 29 females, aged between 6 and 13 years) out of 2049 with cerebral palsy who visited Morinomiya Hospital, the regional center hospital for CP in West Japan. The inclusion criteria were (1) gestational age under 36 weeks at birth, (2) clear history of postnatal intraventricular hemorrhage, and (3) age at investigation over 6 years old. Those without sufficient imaging study or functional evaluation were excluded. METHODS: The participants were divided into four groups according to the presence of post-hemorrhagic hydrocephalus (PH) and cerebellar injury (CI): PH+/CI+, PH+/CI-, PH-/CI+, and PH-/CI-. Type of CP, ability to walk, verbal function, the incidence of severe visual impairment, and the complication of epilepsy were investigated and compared among the groups. RESULTS: The gestational ages of the participants were between 22 and 34 weeks, and their birth weight was between 412 and 1788 g. PH and CI were found in 39 (57%) and 40 (58%) children, respectively. Both the PH+/CI+ group (n=31) and the PH-/CI+ group (n=9) showed significantly lower walking and verbal abilities and a higher incidence of epilepsy than the PH-/CI- group (n=21), while the PH+/CI- group showed no significant difference from the PH-/CI- group. Severe visual impairment was found only in the PH+/CI+ group and the PH-/CI+ group. CONCLUSIONS: The prevalence of CI in preterm children with CP after IVH (58%) was almost the same as that of PH. CI is one of the most significant complications in preterm infants, affecting motor and verbal functions and being associated with epilepsy more than PH.

Prognostic factors for acute encephalopathy with bright tree appearance.

OBJECTIVE: To determine the prognostic factors for encephalopathy with bright tree appearance (BTA) in the acute phase through retrospective case evaluation. METHODS: We recruited 10 children with encephalopathy who presented with BTA and classified them into 2 groups. Six patients with evident regression and severe psychomotor developmental delay after encephalopathy were included in the severe group, while the remaining 4 patients with mild mental retardation were included in the mild group. We retrospectively analyzed their clinical symptoms, laboratory data, and magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) findings. RESULTS: Patients in the severe group developed subsequent complications such as epilepsy and severe motor impairment. Univariate analysis revealed that higher maximum lactate dehydrogenase (LDH) levels (p=0.055) were a weak predictor of poor outcome. Maximum creatinine levels were significantly higher (p<0.05) and minimal platelet counts were significantly lower (p<0.05) in the severe group than in the mild group. Acute renal failure was not observed in any patient throughout the study. MRS of the BTA lesion during the BTA period showed elevated lactate levels in 5 children in the severe group and 1 child in the mild group. MRI performed during the chronic phase revealed severe brain atrophy in all patients in the severe group. CONCLUSIONS: Higher creatinine and LDH levels and lower platelet counts in the acute phase correlated with poor prognosis. Increased lactate levels in the BTA lesion during the BTA period on MRS may predict severe physical and mental disability.

Trinucleotide insertion in the SMN2 promoter may not be related to the clinical phenotype of SMA.

BACKGROUND: More than 90% of spinal muscular atrophy (SMA) patients show homozygous deletion of SMN1 (survival motor neuron 1). They retain SMN2, a highly homologous gene to SMN1, which may partially compensate for deletion of SMN1. Although the promoter sequences of these two genes are almost identical, a GCC insertion polymorphism has been identified at c.-320_-321 in the SMN1 promoter. We have also found this insertion polymorphism in an SMN2 promoter in an SMA patient (Patient A) who has SMA type 2/3. PURPOSE: The aims of this study were to determine the frequency of the GCC insertion polymorphism in SMA patients, and to evaluate its effect on SMN transcription efficiency. PATIENTS AND METHODS: Fifty-one SMA patients, including Patient A, were involved in this study. SMN2 transcript levels in white blood cells were measured by real-time polymerase chain reaction. Screening of the GCC insertion polymorphism was performed using denaturing high-pressure liquid chromatography. The transcription efficiency of the promoter with the insertion mutation was evaluated using a reporter-gene assay. RESULTS: All SMA patients in this study were homozygous for SMN1 deletion. Patient A retained two copies of SMN2, and showed only a small amount of SMN2 transcript in white blood cells. We detected a GCC insertion polymorphism at c.-320_-321 only in Patient A, and not in 50 other SMA patients. The polymorphism had a slight but significant negative effect on transcription efficiency. DISCUSSION AND CONCLUSION: Patient A was judged to be an exceptional case of SMA, because the GCC insertion polymorphism rarely exists in SMN1-deleted SMA patients. The GCC insertion polymorphism did not enhance the transcriptional efficiency of SMN2. Thus, this GCC insertion polymorphism in the SMN2 promoter may not be associated with the milder phenotype of the patient. Patient A suggests that there are other unknown factors modifying the clinical phenotype of SMA.