Epilepsy, electroclinical features, and long-term outcomes in Pitt-Hopkins syndrome due to pathogenic variants in the TCF4 gene

BACKGROUND AND PURPOSE

Pitt-Hopkins syndrome (PTHS) is a rare neurodevelopmental disorder caused by deletions/variants in the TCF4 gene. Seizures may be present in up to half of the patients, leading to a more severe disease burden. This study aims to analyse the electroclinical phenotype, treatment options, and long-term outcomes of epilepsy in PTHS.

METHODS

A multicentre observational cohort study was performed, and the electroclinical data of PTHS individuals affected by epileptic seizures were retrospectively reviewed and analysed.

RESULTS

The series includes 21 patients (11 female) with a median age at seizure onset of 2 years (range = 0.5-8). The median time of follow-up was 7.9 years (range = 2-27). Both generalized and focal epilepsies were present at the same prevalence (42.8%), whereas a minority of patients presented developmental and epileptic encephalopathies (14.4%). At the long-term follow-up, 42.8% achieved seizure freedom, whereas 42.8% developed drug-resistant epilepsy (DRE). The age at seizure onset was found to be an independent predictor for seizure outcome; in this regard, patients having seizure onset after the age of 2 years were more prone to achieve seizure freedom (odds ratio = 0.04, 95% confidence interval = 0.003-0.53; p = 0.01). During evolution, seizures tended to settle down, and even in patients with DRE, seizures tended to persist at a lower frequency and appeared to be more easily manageable over time.

CONCLUSIONS

This study provides new insight into the natural history of epilepsy in PTHS. Better characterization of epileptic phenotype and prompt tailored treatment improve overall management and quality of life.

The importance of TCF4 gene in the etiology of recurrent depressive disorders

BACKGROUND

A recurrent depressive disorder is one of the most commonly diagnosed disease entities among psychiatric disorders. The prevalence and morbidity of depression are constantly increasing. Numerous studies have demonstrated the role of genetic factors in the etiology of depressive disorders. Many studies are being conducted to identify genes that predispose to depression. The purpose of this study was to investigate the role of TCF4 gene in the etiology of recurrent depressive disorders and, in particular, to assess expression of the TCF4 gene at the mRNA and protein level in patients with recurrent depressive disorders versus healthy individuals.

MATERIAL AND METHODS

The examined population consisted of 170 individuals suffering from depression and 90 healthy individuals. The expressions of the TCF4 gene at the mRNA and protein level were assessed.

RESULTS

Decreased TCF4 expression at the mRNA and protein level was found in patients with depressive disorder versus healthy individuals. Expression of the studied gene was not affected by the patients' sex and age. The statistical analysis also showed no correlation between the expression of TCF4 at the mRNA and protein level and the number of episodes or the severity of symptoms. Among the clinical manifestations of depression, only the duration of the illness correlated with the expression of TCF4 at the mRNA level.

CONCLUSIONS

Expression of TCF4 at the mRNA and protein level may be significant in the pathomechanism of recurrent depressive disorder and it is not dependent on sex and age.

A case of Pitt-Hopkins syndrome presented with Angelman-like syndromic phenotypes

Pitt-Hopkins syndrome (PTHS), caused by a TCF4 gene mutation, is a condition characterized by intellectual disability and developmental delay, breathing anomalies, epilepsy, and distinctive facial dysmorphism [1]. Its diverse clinical appearance causes pediatricians to confuse it with Angelman syndrome, which is considered one of the family members of Angelman-like syndrome. Herein, we report on a 4 y/o boy with PTHS and discuss its similarities and differences with Angelman syndrome. In doing so we hope to provide a feasible pathway to diagnose rare diseases, especially Angelman-like syndrome.

Monozygotic twins discordant for 18q21.2qter deletion detected by array CGH in amniotic fluid

Discordant chromosomal anomalies in monozygotic twins may be caused by various timing issues of erroneous mitosis and twinning events. Here, we report a prenatal diagnosis of heterokaryotypic monozygotic twins discordant for phenotype. In a 28-year-old woman, ultrasound examination performed at 26 weeks of gestation, detected intrauterine growth restriction and unilateral cleft lip and palate in twin B, whereas twin A had normal fluid, growth and anatomy. Molecular karyotyping in twin B identified a 18q21.2qter deletion, further confirmed by FISH analysis on amniocytes. Interestingly, in twin A, cytogenetic studies (FISH analysis and karyotype) on amniocytes were normal. Genotyping with microsatellite markers confirmed the monozygosity of the twins. At 32 weeks of gestation, selective termination of twin B was performed by umbilical cord coagulation and fetal blood samples were taken from the umbilical cord in both twins. FISH analyses detected mosaicism in both twins with 75% of cells being normal and 25% harboring the 18qter deletion. After genetic counseling, the parents elected to terminate the second twin at 36 weeks of gestation. In postmortem studies, FISH analyses revealed mosaicism on several tissues in both twins. Taking into account this observation, we discuss the difficulties of genetic counseling and management concerning heterokaryotypic monozygotic twins.