Genetic Testing for Global Developmental Delay in Early Childhood.

Importance: Global developmental delay (GDD) is characterized by a complex etiology, diverse phenotypes, and high individual heterogeneity, presenting challenges for early clinical etiologic diagnosis. Cognitive impairment is the core symptom, and despite the pivotal role of genetic factors in GDD development, the understanding of them remains limited. Objectives: To assess the utility of genetic detection in patients with GDD and to examine the potential molecular pathogenesis of GDD to identify targets for early intervention. Design, Setting, and Participants: This multicenter, prospective cohort study enrolled patients aged 12 to 60 months with GDD from 6 centers in China from July 4, 2020, to August 31, 2023. Participants underwent trio whole exome sequencing (trio-WES) coupled with copy number variation sequencing (CNV-seq). Bioinformatics analysis was used to unravel pathogenesis and identify therapeutic targets. Main Outcomes and Measures: The main outcomes of this study involved enhancing the rate of positive genetic diagnosis for GDD, broadening the scope of genetic testing indications, and investigating the underlying pathogenesis. The classification of children into levels of cognitive impairment was based on the developmental quotient assessed using the Gesell scale. Results: The study encompassed 434 patients with GDD (262 [60%] male; mean [SD] age, 25.75 [13.24] months) with diverse degrees of cognitive impairment: mild (98 [23%]), moderate (141 [32%]), severe (122 [28%]), and profound (73 [17%]). The combined use of trio-WES and CNV-seq resulted in a 61% positive detection rate. Craniofacial abnormalities (odds ratio [OR], 2.27; 95% CI, 1.45-3.56), moderate or severe cognitive impairment (OR, 1.69; 95% CI, 1.05-2.70), and age between 12 and 24 months (OR, 1.57; 95% CI, 1.05-2.35) were associated with a higher risk of carrying genetic variants. Additionally, bioinformatics analysis suggested that genetic variants may induce alterations in brain development and function, which may give rise to cognitive impairment. Moreover, an association was found between the dopaminergic pathway and cognitive impairment. Conclusions and Relevance: In this cohort study of patients with GDD, combining trio-WES with CNV-seq was a demonstrable, instrumental strategy for advancing the diagnosis of GDD. The close association among genetic variations, brain development, and clinical phenotypes contributed valuable insights into the pathogenesis of GDD. Notably, the dopaminergic pathway emerged as a promising focal point for potential targets in future precision medical interventions for GDD.

Compound heterozygous pathogenic variants in the GALC gene cause infant-onset Krabbe disease.

BACKGROUND: Krabbe disease, also called globoid cell leukodystrophy, is an autosomal recessive disease caused by a deficiency of lysosomal galactocerebrosidase. Infantile Krabbe occurring before 12 months of age accounts for most cases. Typical clinical features include irritability, seizures, peripheral neuropathy, and progressive neurodegeneration. METHODS: We collected and summarized the clinical and genetic data of an 8-month-old boy who demonstrated Krabbe disease onset at around 6 months. Potential pathogenic variants were screened by whole exome sequencing, and effects of candidate variants on alternative transcript and truncated protein were further validated at the RNA and protein level. RESULTS: Galactocerebrosidase activity was nearly absent in his blood, and whole exome sequencing revealed compound heterozygous variants [NM_000153.4: (c.658C>T); (c.328+5G>T)] in galactosylceramidase (GALC). The variant c.328+5G>T was predicted to alter splicing, and the abnormal isoform transcript was validated by observation of abnormal RNA isoforms. The variant c.658C>T was predicted to cause truncation of the protein, which was validated by western blotting. CONCLUSIONS: Our findings revealed compound heterozygous variants with solid experimental results for Krabbe disease and provides strong evidence for further Krabbe disease screening and clinical consulting. As a rare inherited systemic disorder, genetic variants in Krabbe disease should be investigated, as experimental validation for clinical diagnosis is needed.

Role of Hypoxia-Inducible Factors 1α (HIF1α) in SH-SY5Y Cell Autophagy Induced by Oxygen-Glucose Deprivation.

BACKGROUND HIF-1α plays an important role in hypoxia-ischemia brain damage. Accumulating evidences demonstrates that HIF-1α can contribute to cell autophagy. Oxygen-glucose deprivation (OGD) is a commonly used ischemic model in vitro. Our study was performed to investigate the influences of HIF-1α on autophagy in SH-SY5Y cells under OGD treatment. MATERIAL AND METHODS An OGD model was constructed in SH-SY5Y cells. PI method and MTT assay were used to test cell death and viability, respectively. Western blot assay was used to estimate the protein levels of HIF-1α and LC3. Quantitative GFP-LC3 light microscopy autophagy assay was performed for SH-SY5Y cells. 2ME2 and siRNA-HIF-1α were applied to investigate the effects of HIF-1α-knockdown on LC3 expression. Additionally, 3-MA (autophagy inhibitor) and autophagy inducer rapamycin (Rapa) were used to investigate the effects of autophagy on cell survival under OGD condition. RESULTS Under OGD, the apoptosis of SH-SY5Ycells was increased while cell viability rate was decreased. The expression of HIF-1α was increased along with the advancement of OGD treatment and achieved the highest level at 24 h. However, inhibiting HIF-1α expression decreased the cell apoptosis and increased cell viability. LC3-II expression was gradually increased with the duration of OGD condition and knockdown of HIF-1α resulted in decreased expression of LC3. Inhibiting autophagy significantly enhanced the viability and reduced the apoptosis of SH-SY5Y cells, while enhancing autophagy showed the opposite effects. CONCLUSIONS Enhanced expression of HIF-1α may be related to autophagy activation in SH-SY5Y cells, thus contributing to ischemic/hypoxic brain damage.

[Effect of botulinum toxin A injection in the treatment of gastrocnemius spasticity in children aged 9-36 months with cerebral palsy: a prospective study].

OBJECTIVE: To investigate the long-term clinical efficacy and adverse effects of botulinum toxin-A (BTX-A) injection in the treatment of gastrocnemius spasticity in children aged 9-36 months with cerebral palsy. METHODS: Eighty children aged 9-36 months with cerebral palsy and gastrocnemius spasticity were selected and randomly divided into a BTX-A injection group and a conventional treatment group (n=40 each). The children in the BTX-A injection group received injections of BTX-A guided by color Doppler ultrasound and 4 courses of rehabilitation training after injection. Those in the conventional treatment group received 4 courses of the same rehabilitation training alone. Before treatment and at 1, 2, 3, and 6 months after treatment, the modified Tardieu scale (MTS) was applied to assess the degree of gastrocnemius spasticity, the values in the passive state measured by surface electromyography (sEMG) were applied to evaluate muscle tension, and the Gross Motor Function Measure (GMFM) was used to evaluate gross motor function. RESULTS: Compared with the conventional treatment group, the BTX-A injection group had significantly greater reductions in MTS score and the values in the passive state measured by sEMG (P<0.05), as well as significantly greater increases in joint angles R1 and R2 in MTS and gross motor score in GMFM (P<0.05). No serious adverse reactions related to BTX-A injection were found. CONCLUSIONS: BTX-A injection is effective and safe in the treatment of gastrocnemius spasticity in children aged 9-36 months with cerebral palsy.

Ketogenic diet effects on neurobehavioral development of children with intractable epilepsy: A prospective study.

OBJECTIVE: This study aimed to determine the impact of a ketogenic diet (KD) on neurobehavioral development when used to treat children with intractable epilepsy, confirming the efficacy of the KD, as well as the correlation between early electroencephalography (EEG) changes in the early stage with treatment efficacy. METHODS: We enrolled 42 children who were starting treatment for intractable epilepsy with the classic KD protocol. The total development quotient as well as the development quotients for adaptability, gross motor movements, fine motor movements, language, and individual-social interaction on the Gesell developmental scales were assessed before and after 3, 6, 12, and 18 months of KD treatment. The efficacy assessment was based on changes in seizure frequency after KD as recorded by the parents. We conducted 24-h video-EEG before and after 1 month of KD treatment. RESULTS: Developmental quotients of five energy regions in the Gesell developmental scales assessment were used to compare adaptability (P1=0.000), gross motor movements (P2=0.010), and fine motor movements (P3=0.000); the results showed significant differences. After KD treatment at different time points, 69.0%, 54.8%, 40.5%, and 33.3% patients, respectively, achieved a ≥50% reduction in seizure frequency. The reduction of epileptiform discharges in the awake state after 1 month of KD treatment correlated with the efficacy after 3 months of KD treatment. CONCLUSIONS: Ketogenic diet treatment tends to be associated with improved neurobehavioral development, and more significant improvement can be obtained with prolonged treatment. The KD is safe and effective in treating children with intractable epilepsy. Early EEG changes correlate with clinical efficacy, to a certain degree.

[Therapeutic effects of different doses of botulinum toxin A injection on tiptoe deformation in children with cerebral palsy].

OBJECTIVE: To study the therapeutic effects of different doses of botulinum toxin A (BTX-A) injection on tiptoe deformation in children with cerebral palsy. METHODS: A total of 256 children with tiptoe deformation due to spastic cerebral palsy were classified into group A (muscle tension levels I-II, n=147) and group B (muscle tension levels III-IV, n=109). Group A was randomly divided into group A1 (injected with high-dose BTX-A, n=73) and group A2 (injected with low-dose BTX-A, n=74). Group B was randomly divided into group B1 (injected with high-dose BTX-A, n=55) and group B2 ( injected with low-dose BTX-A, n=54). The dose of BTX-A was 6 U/kg for groups A1 and B1 and was 3 U/kg for groups A2 and B2. Before the injection and at 1,2,6, and 12 months after injection, the muscle tension of limbs was evaluated with the modified Ashworth Scale, and the recovery of motor function of lower limbs was assessed with the Gross Motor Function Measure (GMFM). RESULTS: Before and after treatment, there were no significant differences in Ashworth and GMFM scores between groups A1 and A2 (P>0.05). After treatment, group B1 had a significantly reduced Ashworth score and a significantly increased GMFM score, and group B1 had a significantly lower Ashworth score and a significantly higher GMFM score compared with group B2 (P<0.05). For groups A and B, Ashworth score gradually declined post-treatment, reached the lowest point at 3 months after treatment, and returned to the level before treatment at 12 months after treatment; GMFM score gradually increased post-treatment and reached the peak level at 12 months after treatment (P<0.05). CONCLUSIONS: The level of muscle tension should be considered when BTX-A injection is used for treating tiptoe deformation in children with cerebral palsy. It makes no difference to use high- or low-dose BTX-A when the muscle tension level is within I-II, but high-dose BTX-A has a better performance in reducing muscle tension and improving motor function when the muscle tension level is within III-IV.

[Clinical analysis of 322 cases of non-epileptic cerebral palsy].

OBJECTIVE: To study the clinical features of non-epileptic seizures associated with cerebral palsy (CP) in children. METHODS: A total of 1 198 children with CP (age: 9 months to 6 years) were enrolled. The children with paroxysmal events were monitored by 24 hrs video-EEG (VEEG) to make sure the seizures were epileptic or non-epileptic. The symptoms, age, CP types and EEG features were observed in children with non-epileptic CP. RESULTS: Five hundred and seventy-eight children (48.24%) presented paroxysmal events. The seizures were epileptic in 231 children (19.28%) and non-epileptic in 322 cases (26.88%). In the 322 cases of non-epileptic CP, the paroxysmal events were of various kinds, including non-epileptic seizure tonic, seizure shake head, shrug shoulder or head hypsokinesis, cry or scream, panic attacks, sleep myoclonic and stereotyped movement. One hundred and fifty-eight (49.1%) out of the 322 children demonstrated nonspecific EEG abnormalities. One hundred and eleven children (34.5%) were misdiagnosed as epilepsy in primary hospitals. The CP children less than one year old showed higher frequency of non-epileptic seizures than the age groups over 1 year and 3 to 6 years. The frequency of non-epileptic seizures was the highest in children with spastic CP (168 cases, 52.2%), followed by dyskinetic CP (69 cases, 21.4%) and mixed type CP (65 cases, 20.2%). CONCLUSIONS: The paroxysmal events in children with CP partially are non-epileptic seizures and it is important to differentiate non-epileptic from epileptic seizures. The frequencies of non-epileptic seizures may be associated with a child's age and CP type.

Mutation of acceptor splice site of the SEDL gene in X-linked spondyloepiphyseal dysplasia tarda causes the activation of cryptic splice site.

OBJECTIVE: To further investigate the genetic basis of hereditary X-linked spondyloepiphyseal dysplasia tarda (SEDL) and provide useful information for the prevention and treatment of the disease. METHODS: RT-PCR and cDNA sequencing were used to test mRNA expression of SEDL gene in a patient with 13 bp deletion of SEDL gene involving the acceptor splice site of intron 5. RESULTS: Of two different sizes of mRNA products identified in the patient, the 393 bp product was created due to the activation of cryptic splice site within exon 6; the 433 bp product was completely consistent with the part of genomic sequence on chromosome 8. CONCLUSION: The intragenic deletion that occurred in the acceptor splice site of the 3'region of intron 5 and the 5' coding region of exon 6 results in the activation of a cryptic splice site within exon 6, which causes 47 bp deletion of the resulting mRNA followed by a frameshift that would add two missense amino acids and then be followed by a termination codon (D109-S123del; S124fsX126). In addition, the mutation may activate the transcription of pseudogene SEDLP2 on chromosome 8 to partly complement the function of SEDL protein.

[Association analysis on the polymorphisms of PCOL2 and Sp1 binding sites of COL1A1 gene and the congenital dislocation of the hip in Chinese population].

OBJECTIVE: To investigate the polymorphism distribution of the PCOL2 and Sp1 binding sites of the collagen type I alpha 1(COL1A1) gene in Chinese population and explore their relationship with congenital dislocation of the hip (CDH). METHODS: The PCOL2 polymorphism (-1997 G/T) in COL1A1 promoter and the Sp1 polymorphism (1546 G/T) in intron 1 were genotyped in 243 members from 81 CDH nuclear family trios by the technique of polymerase chain reaction-restriction fragment length polymorphism, and then transmission disequilibrium test was used to analyze the data of genotypes. RESULTS: No statistically significant association was observed between CDH and PCOL2 polymorphism. Significant differences of genotype and allele frequency distributions were detected between the Chinese population and the Caucasian population in Spain, and between the Chinese population and the Caucasian population in America. The allele at the Sp1 site that has been found to be polymorphic in other populations was not found in Chinese. CONCLUSION: There exists racial difference in the distribution of the PCOL2 and Sp1 polymorphisms of COL1A1 gene. The results suggest that the PCOL2 and Sp1 polymorphisms may not be the major susceptibility gene of CDH in Chinese population.

[Glial fibrillary acidic protein mutation in a Chinese girl with infantile Alexander disease].

OBJECTIVE: To investigate the molecular basis of infantile Alexander disease in a Chinese patient, which may yield useful information for further genetic counseling. METHODS: DNA sequencing analysis and restriction endonuclease analysis were used to detect the mutation of glial fibrillary acidic protein (GFAP) gene in a patient with clinically diagnosed Alexander disease, in her parents and in 50 healthy controls. RESULTS: A 249C>T (R79C) mutation was identified in the exon 1 of the GFAP gene but not in her parents and the controls. CONCLUSION: The study on mutation of GFAP gene in Chinese patients with Alexander disease has never been reported previously. The mutation analysis of GFAP gene can provide valuable information for the diagnosis of Alexander disease and can serve as a reliable method of prenatal diagnosis for the family.

[Identification of a novel mutation of the SEDL gene in X-linked spondyloepiphyseal dysplasia tarda].

OBJECTIVE: To investigate further the genetic basis of hereditary X-linked spondyloepiphyseal dysplasia tarda (SEDL). METHODS: Single strand conformation polymorphism (SSCP) combined with polymerase chain reaction and denaturing polyacrylamide gel electrophoresis were used to detect the mutation for the coding exons of SEDL gene as well as their exon/intron boundaries in 5 unrelated Chinese boys clinically diagnosed as having SEDL. DNA sequencing analysis was further used to identify the mutation. RESULTS: The 13 bp deletion mutation consisting of IVS5-2-1delAG and 322-332del TTTTCAATGAA was identified in one of SEDL patients, but not detected in 30 chromosomes from 30 unrelated normal male individuals. CONCLUSION: This is a novel mutation cosegregated with the patient's skeletal disease. The intragenic deletion occurred in the acceptor splice site of the 3' region of intron 5 and the 5' coding region of exon 6, which may result in one or a combination of splicing defects. The results of this study expand the spectrum of SEDL mutations associated with SEDL, and this will help to elucidate further the role of this novel protein in the etiology of this form of osteochondrodysplasia.