# From Genotype to Phenotype of Polish Patients with Pitt–Hopkins Syndrome concerning the Quality of Life and Family Functioning

## TL;DR

This study examines the genetic and clinical features of Polish children with Pitt–Hopkins syndrome and evaluates their quality of life and family impact.

## Contribution

The study provides new genotype-phenotype data and QoL assessments for PTHS patients in Poland.

## Key findings

- All children had TCF4 gene mutations and typical PTHS features like intellectual disability and speech delays.
- Quality of life scores for children and families were below average, with daily activities being the lowest-rated domain.
- Common symptoms included reduced pain response, constipation, drooling, and sensory integration issues.

## Abstract

Background: Pitt–Hopkins syndrome (PTHS) is a rare genetic disorder affecting psychomotor, social, and intellectual development, caused by a mutation in the TCF4 gene. The study aims to gather the phenotype and genotype data of PTHS patients from Poland and to assess the quality of life (QoL) and the impact of the disorders on the family. Methods: Eight families with PTHS participated in the study. To obtain data, the following standardized questionnaires were used: Questionnaire on Clinical Problems (QCP), the PedsQL™ Family Impact Module, and the QL-Disability Questionnaire. Additionally, a retrospective analysis of clinical examination, genetic consult, medical history, and genotype of each individual was performed. Results: All of the examined children exhibited a mutation in the TCF4 gene and typical features of PTHS. The most prevalent clinical symptoms in the study group included typical PTHS appearance, intellectual disability (n = 5; as the rest of the patients were too young to be assessed), abnormal speech development (n = 8), reduced pain response (n = 7), constipation (n = 7), drooling (n = 7), cold extremities (n = 7), and disturbances in sensory integration processes (n = 7). The QL-Disability Questionnaire revealed a total QoL score of 67.7/100 for children with PTHS, while the QoL for their families in the PedsQL Family Impact Module was 53.82/100. The highest-rated domain was cognitive functioning (Median (Me) = 67.50; Standard Deviation (SD) = 21.95), while the lowest was daily activities (Me = 25.00; SD = 29.86). Conclusions: The study allowed the collection of data on the phenotype and genotype of children with PTHS living in Poland. Overall, our study showed that the QoL of children with PTHS is impaired.