Rare Disease Report

Autism and Tuberous Sclerosis Complex

DECEMBER 03, 2015
James Radke, PhD
No two people with tuberous sclerosis complex (TSC) have the same symptoms. That is being stressed by the hashtag #iamtsc currently circulating throughout social media. Each patient with TSC is unique and has a unique story.
 
While there is much variety among the TSC population with multiple organs being affected, certain symptoms tend to be more prevalent than others. Seizures are common in TSC patients. So are symptoms of autism spectrum disorder.
 
Due to the large variance in symptoms among the TSC populations, it is important to look for correlations among the symptoms to see if patterns exist that may improve TSC management. Such was the logic behind a group of researchers in Italy who looked at the prevalence of autism spectrum disorder among TSC patients.
 
Their study was designed to: 1) assess the prevalence of ASD in a TSC population; 2) describe the severity of ASD; 3)  identify potential risk factors associated with the development of ASD in TSC patients. The study was published this week in Orphanet Journal of Rare Diseases.

Methods

Forty-two people with TSC were followed at a TSC clinic in Milan, Italy, between September 2013 and July 2014. The patients ranged in age of 4 to 44 years, with a median age of 19.3 years. Clinical, genetic data, and cognitive data. The Social Communication Questionnaire (SCQ) was used as a screening tool for autism spectrum disorder.

Results

Of the 42 patients, 17 (40.5 %) had a SCQ score that is suggestive of ASD (≥15 points). Correlating the SCQ scores with other data collected, the researchers noted the SCQ seemed to be correlated with the person’s cognitive level (i.e., higher SCD scores were linked to persons with lower cognitive abilities).
 
SCQ scores were correlated with with epilepsy, seizure onset before age one year, spasms, mutations in TSC2, cognitive level, sleep disorders, and other psychiatric problems, but not with seizure frequency, tubers localization and gender (see table)

Table. Average SCQ scores for each clinical and genetic feature

 Gender
  Number of patients
  Average SCQ score
Male
18
10.6 ± 7.0
Female
24
11.2 ± 8.5
 

 
 Mutation
   Number of patients
   Average SCQ score
TSC1
10
16.3 ± 6.0
TSC2
30
12.6 ± 8.0
NMI
2
9.5 ± 3.5
P < .03*
 Epilepsy
   Number of patients
   Average SCQ score
Present
36
12.1 ± 7.7
Absent
6
4.2 ± 4.7
  P < .05
 Onset of seizures
   Number of patients
   Average SCQ score
> age1 yr
25
14.0 ± 7.4
> age 1 yr
11
7.5 ± 6.4
  P < .05
 Spasms
   Number of patients
   Average SCQ score
Present
18
15.1 ±7.4
Present
18
8.2 ± 6.6
  P < .05
 Antiepiletic medication
   Number of patients
   Average SCQ score
Monotherapy
13
10.1 ± 9.0
Polytherapy
20
13.6 ± 6.3
  NS
 Seizure frequency
   Number of patients
   Average SCQ score
None
19
9.9 ± 8.0
Monthly
7
15.7 ± 5.3
Weekly
10
13.6 ± 7.8
NS
 IQ
   Number of patients
   Average SCQ score
>70
11
4.8 ± 4.3
<70
19
11.5 ± 6.7
  P < .05
 Sleep Disorders
   Number of patients
   Average SCQ score
Present
9
16.4 ± 8.0
Absent
33
9.4 ± 7.1
  P < .05
 Psychiatric disorders
   Number of patients
   Average SCQ score
Present
17
13.3 ± 8.7
Absent
24
8.6 ± 6.0
  P < .05
*TSC1 vs TSC2

Finally, the researchers found a wide variety of SCQ scores among the patients that is indicative of the wide variety of symptoms and symptom severity seen in the TSC population.

Conclusions

The authors concluded that the prevalence of autism spectrum disorder observed in their study (40.5%) is within the range reported in other studies and confirming the higher risk for this disorder in patients with TSC. Further, epilepsy, infantile spams, and mutations in TSC2 appear to be risk factors for autism spectrum disorder in TSC patients.
 
Early recognition of TSC patients developing autism spectrum disorder symptomatology may help guide treatment.

Reference

Vignoli A, La Briola F, Peron A, et al.  Autism spectrum disorder in tuberous sclerosis complex: searching for risk markers. Orphanet J Rare Dis. 2015;10:154. doi:10.1186/s13023-015-0371-1

 

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