Table 2. Overview of clinical features of PTHS patients, based on personal observation (32) and the studies by Whalen et al17 and Sweatt18 .
| Clinical signs | Total (%) |
|---|---|
| Typical facial appearance: | >95 |
| • Deep-set eyes | |
| • Broad nasal bridge | |
| • Beaked nose | |
| • Down-turned nasal tip | |
| • Pointed nasal tip | |
| • Flaring nostrils | |
| • Wide mouth | |
| • Widely spaced teeth | |
| • Cupid's bow upper lip | |
| • Protruding lower face | |
| • Cup-shaped ears | |
| • Fleshy ears | |
| Severe mental retardation with severe speech impairment | 100 |
| Hypotonia | 70–90 |
| Normal growth parameters at birth | 80–90 |
| Postnatal growth retardation | 10–30 |
| Postnatal microcephaly (or progressive slowing down of head circumference growth) | 25–75 |
| Breathing anomalies | 50–80 |
| • Hyperventilation episodes | 40–60 |
| • Apnea crises | 40–60 |
| Motor incoordination | 50–80 |
| • Severe ataxia | |
| • Broad-based gait | |
| • Incoordination of hand–mouth movements | |
| Ocular anomalies | 50–80 |
| • Strabismus | |
| • Myopia | |
| • Astigmatism | |
| Constipation | 60–80 |
| Seizures (or EEG anomalies)a | 20–90 |
| Happy disposition | 80–95 |
| Stereotypic movements | 70–95 |
| • Bruxism | |
| • Lateral movements | |
| • Hand clapping | |
| • Hand flapping | |
| • Hand–mouth movements | |
| Hand anomalies | 50–70 |
| • Tapering fingers | |
| • Clinodactyly | |
| • Fetal finger pads | |
| • Single palmar crease | |
| • Absent thumb flexion crease | |
| Brain abnormalities | 50–85 |
| • Broadening of ventricles | 20–35 |
| • Corpus callosum hypoplasia | 20–45 |
Abbreviations: EEG, electroencephalographic; MRI, magnetic resonance imaging; PTHS, Pitt–Hopkins syndrome.
a
Differences due to including or not including isolated EEG anomalies.