Clinically, PTLS presents as a milder syndrome than SMS, with distinct characteristics, though PTLS can be mistaken for SMS. Both syndromes are characterized by multiple congenital abnormalities and intellectual disability. A key feature which appears in 80% of cases is autism spectrum disorder. Other unique features of<unk>  include infantile hypotonia, sleep apnea, structural cardiovascular anomalies, cognitive deficits, abnormal social behaviors, learning disabilities, attention-deficit disorder, obsessive-compulsive behaviours, malocclusions, short stature and failure to thrive. After noting that autism is commonly associated with PTLS, researchers at the Centro de Estudios Científicos and the Austral University of Chile genetically engineered a PTLS "model mouse" where the syntenic chromosome segment was duplicated, and examined the social behaviours of these mice versus those without the anomaly (the "wild-type"). One human autism-related symptom is abnormal reciprocal social interaction. The researchers observed that the genetically-engineered mice of both sexes had a slight (statistically insignificant) impairment of their preference of a social target (i.e., a living, breathing mouse) over an inanimate one — the average human will prefer the social target — and preferred to explore newly introduced mice instead of familiar ones, unlike the typical human and mouse preference of a friend over a stranger, demonstrating a change in their liking of social novelty. They also found that male mice, in some scenarios, showed increased anxiety and dominant behaviour than the control group. Anatomically, the engineered mice had a decreased brain-to-body mass ratio and an alteration in the expression of several genes in the hippocampus.
Potocki–Lupski syndrome
Young–Madders syndrome
Lujan–Fryns syndrome
Fox–Fordyce disease
Townes–Brocks syndrome
Frasier syndrome
Young–Simpson syndrome
Fowler's syndrome