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Table 1 Clinical and genetic characteristics of patients with SYN1-related disorders in literature and the study

From: Familial SYN1 variants related neurodevelopmental disorders in Asian pediatric patients

References Garcia et al. [4] Nguyen et al. [11] Sirsi et al. [12]* Guarnieri et al. [16] Peron et al. [15] Darvish et al. [14] Ibarluzea et al. [13] Pedigree A (this study) Pedigree B (this study)
Country (ethnic) England
(unknown)
Canada
(French-Canadian)
America
(Latino)
Italy
(unknown)
Italy
(unknown)
America
(unknown)
Spain
(unknown)
China
(Han)
China
(Han)
Basic information
Sex of probands Male (assumed) Male Male Unknown Male Male Male Male Male
Affected family members Male (10) Male (10);
Female (2)
Male (8);
Female (2)
Male (2) Male (3) Male (2) Male (1) Male (1)
Carrier family members Female (9) Female (8) Female (1) Female (1) Female (1) Unknown Female (5) Female (3) Female (1)
SYN1 variants c.G1068A (p.W356X)
[NM_133399]
c.C1663T
(p.Q555X)
[NM_133399]
c.C1264T
(p.R422X)
[NM_133399]
c.C236G (p.S79W)
[NM_133399]
c.527 + 1G > T
[NM_133399]
c.G1259A
(p. R420Q)
[NM_133399]
c.G796A (p.V266M)
[NM_133399]
c.C1076A (p.T359K)
[NM_133399]
c.C1444T (p.Q482X)
[NM_133399]
Diagnosis Variable epilepsy, learning disabilities, and aggressive behavior X-linked focal epilepsy with reflex related-bathing seizures Focal epilepsy and reflex related- bathing seizures, autism, and intellectual disability Non-syndromic intellectual disability Hot water-sensitive epilepsy Autism and progressive intellectual disability without epilepsy Intellectual disability and paranoid schizophrenia Intellectual disability and complex febrile seizures Epilepsy, behavioral disorders and learning disabilities
Clinical features  
Degree of intellectual disability Normal or mild Normal or mild Moderate to severe Normal or mild ID from early childhood mental regression Mild Profound Moderate
Presence of epilepsy Y Y Y N Y N N Y Y
Onset age of seizures 6–27y 1y8m–50y Early childhood 8y - - 1y 7y
Seizure semiology Tonic–clonic, reflex, and partial and complex-partial seizures Spontaneous complex partial seizures and reflex seizures triggered by bathing Focal seizures and reflex seizures triggered by bathing Hot water sensitive seizures at the beginning, subsequently followed by nonreflex seizures - - Tonic–clonic seizures triggered by fever Tonic–clonic seizures
Seizure frequency Episodic Episodic 1–2 times per month Unknown - - Only 2 times Episodic
Seizure control or not Y Most affected members have achieved seizure control Intractable to AEDs, seizures reduce about 50% by VNS Unknown Y Y
Abnormal behavior
Aggression Y N N N N N N Y
Autistic traits Y Y Y N Y Y N N
EEG findings Some evidence of spikes in the left temporal region or normal Rhythmic theta activity over temporal head regions Spikes on the left temporal region Bilateral rhythmic theta activity over the frontocentral and vertex regions Normal Occasional sharp-waves occurring in bilateral frontal areas during sleep
Brian MRI imaging Normal Hippocampal atrophy Normal Marked generalized frontal atrophy Normal Normal
Other findings Macrocephaly N N N N Sphincter dysfunction N Bilateral esotropia Ametropia
  1. AEDs anti-epileptic drugs, EEG electroencephalography, ID intellectual disability, MRI magnetic resonance imaging, m month, N no, Y yes, y year, VNS vagal nerve stimulator
  2. *The pedigree in the study has a maternal family history of epilepsy but lacks familial genetic results due to financial reasons