Pitt–Hopkins syndrome
Rare genetic disorder with developmental delay and distinctive facial features.
Pitt–Hopkins syndrome (PTHS) is a rare genetic disorder marked by developmental delay, moderate to severe intellectual disability, distinctive facial features, and episodes of rapid breathing followed by pauses in breathing. Seizures are common, occurring in about 37 to 50 percent of cases. The condition falls within the group of Rett-like syndromes and shares similarities with Angelman syndrome, Rett syndrome, Mowat–Wilson syndrome, and ATR-X syndrome.
As understanding of PTHS grows, the range of developmental challenges has expanded to include anxiety, autism, ADHD, and sensory processing disorders. The syndrome results from a problem on chromosome 18 that leads to insufficient activity of the TCF4 gene. People with PTHS often experience self-injury and aggressive behaviors, typically linked to autism and sensory issues.
Although PTHS has traditionally been associated with severe cognitive impairment, measuring true intelligence is difficult because of motor and speech difficulties. With augmentative communication and modern therapies, many individuals achieve more than was once expected, and it is now clear that cognitive abilities vary more widely than earlier scientific literature suggested. There is no cure, but symptoms can be treated. Researchers have developed cell and rodent models to test potential therapies. PTHS is estimated to occur in 1 in 31,000 to 1 in 41,000 people.
**Signs and symptoms**
PTHS can be noticed in early childhood. In infants, early signs include a distinctive lower face and a high nasal root. Characteristic facial features include a broad nasal bridge with a bulbous tip, a wide mouth, a Cupid's bow-shaped philtrum, prominent ears, and thin eyebrows. Flat feet, overlapping toes, and fetal pads are also common. Short stature and scoliosis occur frequently. Other features may include constipation and other gastrointestinal problems, microcephaly, nearsightedness, strabismus, and minor brain abnormalities. Adults with PTHS may have trouble with speech. Craniofacial features, important for diagnosis, become more noticeable with age. Children with PTHS typically have a happy, excitable demeanor with frequent smiling, laughter, and hand-flapping, though they can also experience anxiety and behavioral issues.
**Gastrointestinal**
Gastrointestinal problems are common and include constipation, reflux, and burping.
Quick Facts
- Field
- Psychiatry, Medical genetics
- Frequency
- 1 in 31,000 to 1 in 41,000 people
Facts from the source article.
Lore & Background
Pitt–Hopkins syndrome was first described in 1978 by D. Pitt and I. Hopkins at the Children's Cottages Training Centre and Royal Children's Hospital in Melbourne, Australia, in two unrelated patients. The genetic cause was identified in 2007 as a haploinsufficiency of the transcription factor 4 (TCF4) gene on the long arm of chromosome 18. The mutational spectrum includes point mutations (40%), small deletions/insertions (30%), and deletions (30%), all appearing to be de novo mutations.
Reader's Guide
Pitt–Hopkins syndrome is significant as a rare genetic disorder that broadens the understanding of developmental and intellectual disabilities. It is part of the clinical spectrum of Rett-like syndromes and is clinically similar to Angelman syndrome, Rett syndrome, Mowat–Wilson syndrome, and ATR-X syndrome. The developmental spectrum is widening to include anxiety, autism, ADHD, and sensory disorders. While traditionally associated with severe cognitive impairment, true intelligence is difficult to measure due to motor and speech difficulties; augmentative communication and progressive therapies have shown that many individuals can achieve more than initially thought. No cure exists, but symptoms can be treated. Researchers have developed cell and rodent models to test therapies. The condition highlights the importance of genetic testing and multidisciplinary care involving neurologists, ophthalmologists, pulmonologists, and gastroenterologists.
Did You Know?
- Pitt–Hopkins syndrome is estimated to occur in 1:31,000 to 1:41,000 people.
- Epilepsy is reported in 37%–50% of cases, with onset possible from infancy through adulthood.
- Gastrointestinal difficulties such as constipation, reflux, and burping are common and can occur over the entire lifespan.
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