Assessment of tuberous sclerosis-associated neuropsychiatric disorders using the MINI-KID tool: a pediatric cohort study

Background: Tuberous sclerosis-associated neuropsychiatric disorders (TANDs) have not been studied before in China. We aimed to assess the psychiatric level of TAND using the Mini International Neuropsychiatric Interview for Children (MINI-KID) in China. Results: A total of 83.16% of patients (79/95) had at least one TAND, and 70.53% (67/95) had an intellectual disability. The MINI-KID tool diagnosed a total of 16 neuropsychiatric diseases, the most common of which were attention-decit/hyperactivity disorder (ADHD) (51.58%, 49/95) and social anxiety disorder (41.05%, 39/95). The number of children with neuropsychiatric diseases in the TSC group was signicantly greater than the number in the normal development group (p <0.0001). Epilepsy before the age of 2 years, a seizure frequency of more than once a month, and the use of more than 2 antiepileptic drugs were closely associated with the occurrence of TAND. Conclusion: The MINI-KID can be used as a standardized tool to examine the psychiatric level of TANDs in children with TSC aged 6-16 years. The rate of neuropsychiatric diseases in children with TSC reached 83.16%. Early onset of epilepsy, frequent seizures, and refractory epilepsy are risk factors for TAND. Early, reasonable, and rapid control of seizures is related to reducing the risk of neuropsychiatric illness in children with epilepsy.

and to compare with a normally developing population. To the best of our knowledge, this is at present the largest-sample TAND assessment of children in China, and it is also the rst TAND study using the MINI-KID.
All 95 children were genetically tested, and the TSC1:TSC2:NMI (no mutation identi ed) ratio was 27:58:10. There were more sporadic cases than familial cases (n = 55 vs n = 40). Sixty-seven children had an intellectual disability (IQ≤70) (70.53%), 34 (35.79%) had mild to moderate intellectual disability (IQ 35-70), and 33 (34.74%) had severe intellectual disability (IQ<35). Of the 95 children, 76 had a history of epilepsy (80.00%), and 49 of the patients with TSC and epilepsy developed drug-resistant epilepsy (64.47%). The average age at seizure onset was 2.50±3.59 years, and the duration was 7.65±4.37 years. Eighty-seven patients had cortical tubers, 86 children had subependymal nodules (SENs), and 3 patients had subependymal giant cell astrocytoma (SEGA).  (Table 2). ADHD, social anxiety disorder, panic disorder, speci c phobia, PDD, (mild) manic episodes, agoraphobia, tic disorder, separation anxiety disorder, major depressive episode, suicide and obsessive-compulsive disorder were signi cantly different between the TSC and control groups (p<0.05) ( Table 2). Among TSC patients, 73.68% had two or more TANDs. The rates of psychiatric disorders in those with different levels of ID and different genotypes are shown in Supplementary Table 1 and Supplementary Table 2.

Discussion
To make screening for TANDs easy and convenient, the Neuropsychiatry Panel offers the TAND Checklist, which is a simple framework for a conversation about TANDs. Its results are used to indicate a possible clinical diagnosis to guide patients in further evaluation and in seeking more specialized treatment [3]. Unfortunately, there is currently no Chinese version of the TAND Checklist available. Therefore, the Chinese version of the MINI-KID, which has been well validated in terms of reliability and validity, would be a very useful attempt in the area of psychiatric disorders.
To our knowledge, this is the rst cross-sectional study of TANDs using the MINI-KID, and it is also the largest-sample TAND cohort study in China. As one of the large advanced pediatric neurological disease centers in China, the Children's Hospital of Fudan University mainly receives TSC children with epilepsy or even drug-refractory epilepsy and other complications from all over China. The rate (70%) of children with ID is slightly higher than that previously reported (44%-64%) [13][14][15] but close to that reported by Chinese scholars (72%) [16]. The rate of neuropsychiatric disorders in children with TSC is signi cantly higher than that in patients with normal neurodevelopment. As in previous studies, TANDs can exist in childhood and adolescence [3,4,17,18]. The lifetime prevalence of TANDs is approximately 90% [3]. Anxiety, depression, and ADHD are more common in TSC patients [18].
In our cohort, a total of 77 TSC children had neuropsychiatric disorders, for a rate of 81.05%, which far exceeded our expectation. However, clinicians pay far less attention to mental illness than neurological disorders (such as epilepsy and SEGA). As reported in previous studies, less than 40% of more than 2,000 patients from 31 countries have had an intelligence assessment, and the proportion of missing TANDs data is high. This demonstrates that TANDs are not adequately identi ed and processed even at TSC specialty centers [18]. Our study suggests that the disease burden of TSC is far greater than previously realized, which will serve as a basis for a better distribution of medical resources.
According to Prather & de Vries et al. [19,20], autistic spectrum disorder (ASD) and ADHD are the most common TANDs in children, and anxiety/mood disorders are the most common in adults. The incidence of ADHD has varied by study method and diagnostic criteria from 30 to 60% [21][22][23][24]. The MINI-KID serves as a short, standardized, universal assessment tool to systematically assess parent reports of healthrelated neuropsychiatric disorders in children with chronic diseases [25][26][27]. To our knowledge, this report is the rst application of the MINI-KID tool in a TSC cohort to accurately screen and diagnose TANDs. We found that ADHD, social anxiety disorder, panic disorder, PDD and speci c phobia were the most common in this group. The rate of ADHD in our cohort was signi cantly higher than that in the TOSCA cohort (51.58% vs. 22.4%) [7], and we suggest the following possible reasons: (1) The age distribution of children in the TOSCA cohort was 0-18 years old, while the age distribution of children in our cohort was 6-16 years old, which was consistent with the high incidence age of ADHD diagnosis. (2) Our cohort included TSC patients from all over the country. In some areas, a comprehensive and systematic treatment standard has not been established, and clinicians do not even know enough about TAND to intervene in time.
Although the rate of anxiety was very high in previous cohorts [7,17,18], the diagnosis rate of anxiety was lower in our study (25.80%-56.00% vs. 10.53%), while the rate of depression was approximately the same (8.20% vs. 6.32%). In the future, attention should be paid to screening children for emotional disorders and anxiety responses. Our results are comparable to those of a cohort study of 32 samples in Italy [8].
We sought to identify the risk factors associated with the occurrence of TANDs and found that an earlier onset age (<2 years), more frequent seizures (more than 1 seizure per month), and the use of more antiepileptic drugs (≥2) are closely related to the occurrence of TANDs. These are similar to previous studies [7,17,19]. It is therefore recommended that epilepsy be diagnosed as early as possible and controlled as soon as possible to reduce the risk of neuropsychological disorders, but it does not seem to stop TAND completely [28]. Although the statistics showed that children with a TSC1/TSC2 gene mutation are more likely to have multiple TANDs (≥ 2) than children with NMI (p = 0.004), all children with TSC are at signi cantly increased risk of TAND and should therefore be screened [2].
This study presents several limitations. This was a cross-sectional study of a single center, and future multicenter prospective studies are needed to further verify the results. In addition, this study used only one method to explore the mental health of children with TSC and did not use the TAND checklist for comparison. The study population included children 6-16 years of age, excluding younger children.

Conclusion
The MINI-KID scale can be used as a standardized tool to examine the psychiatric level of TANDs in children with TSC aged 6-16 years. The rate of neuropsychiatric diseases in children with TSC is very high, reaching 83.16%, which is signi cantly higher than that in normally developing children. ADHD is the most common psychiatric disorder identi ed with the MINI-KID in this study and can occur in 51.58% of children. Epilepsy onset before the age of 2 years, seizures of more than once a month, and the use of more than 2 antiepileptic drugs are closely related to the occurrence of TANDs. Early screening, diagnosis and intervention are critical for early-onset epilepsy. In addition, controlling seizures as soon as possible and rational use of anti-epileptic drugs are related to reducing the risk of TAND.

Study population
This cross-sectional study was carried out from September 2019 to November 2019. The TSC children were recruited from among all patients with TSC 6-16 years old who were treated in the Department of Neurology at the Children's Hospital of Fudan University. All patients met the latest diagnostic criteria for tuberous sclerosis [2] and were examined for the TSC1/TSC2 genes. The exclusion criterion was refusal to participate.
We also recruited children with normal nervous systems as the control group in the health examination center of Children's Hospital of Fudan University and matched them by age and sex. The criteria for children with normal nervous system development were as follows: (1) normal motor and language development; (2) no history of seizures or other neurological diseases; (3) no other chronic diseases (such as diabetes, asthma or cancer); and (4) no family history of mental illness in rst-degree relatives. The exclusion criterion was parental refusal to provide informed consent. Children with normal development were screened by the deputy chief physician and attending physician of the neurology department, who each had more than 5 years of experience.
Written informed consent was received from all participating families. This study was approved by the ethics committee of the Children's Hospital of Fudan University.

Standardized questionnaire
After providing informed consent, parents or guardians were invited to participate in interviews, and standardized questionnaires were used to obtain demographic and clinical data. The demographic data collected were date of birth, gender, ethnicity, parental education level, family income, and residence. Cognitive assessment was performed using the Wechsler Intelligence Scale for Children in Chinese (WISC-C). The clinical data collected were growth and development, family history, age at onset of epilepsy, duration of epilepsy, current number of antiepileptic drugs, frequency of seizures, spasm, and TSC clinical manifestations.

MINI-KID (parent version)
Parents or guardians of the TSC children were interviewed using the MINI-KID (parent version) for children and adolescents. The Chinese version of the MINI-KID (parent version) 5.0 was translated by Liu YX and others from the Peking University Institute of Mental Health in 2010. Liu YX's study and other studies have con rmed that the Chinese version of the MINI-KID (parent version) has good reliability and validity [29] and that the parent version is more sensitive than the child version [30,31].
The MINI-KID is a structured diagnostic scale designed according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV), and the International Classi cation of Disease, 10th version (ICD-10). The scale has 25 modules to diagnose 24 mental illnesses and suicidal tendencies in children and adolescents between the ages of 6 and 16 years old [9,12]. Each module includes a screening questionnaire and a diagnostic questionnaire. The MINI-KID was administered in this study by highly trained neurologists (minimum 5 years of experience in the diagnosis of neuropsychiatric diseases in children), and the diagnosis was based solely on whether the responses to the screening questions were positive. All questions had a "yes/no" response format [9,12]. It took approximately 30-45 minutes to complete the assessment.
All parents of children in this study were administered the questionnaire face-to-face after signing the informed consent form.

Statistical Analysis
Continuous variables are presented as the mean and standard deviation (SD). Continuous variables were analyzed using ANOVA F-test, and categorical variables were analyzed using chi-square or Fisher's exact tests. Multivariate logistic regression models were performed with each TAND risk factor as an independent variable. Those known risk or protective factors of TAND were included in our analysis regression models. We adjusted for gender (male/female), maternal education (years) (≤9/9-12/>12), paternal education (years) (≤9/9-12/>12), family income (RMB) (<5000/5000-10000/>10000) and residence (suburban or rural/urban) in the adjusted model. Two-sided p < 0.05 was statistically signi cant. All analyses were performed by using JMP Pro 15.

Declarations
Ethics approval and consent to participate This study was approved by the Children's Hospital of Fudan University Institutional Review Board prior to the recruitment of subjects (2018-No.26).

Consent for publication
All presentations of case reports provided consent for publication.

Availability of data and material
The datasets used during and/or analyzed during the current study are available from the corresponding author on request.