PURA

Clinical Characteristics

Due to the recent discovery of PURA syndrome and the rarity of this condition, there is a limited understanding of the phenotype.

To date, it is believed that all of those affected have moderate-severe intellectual disability. In the majority of patients there were non-specific symptoms in the neonatal period, overlapping with other syndromes. These include hypersomnolence, hypotonia, hypothermia, breathing difficulties, feeding difficulties, and exaggerated startle. There are also reports of prenatal and postnatal hiccupping.

The condition seems to affect multiple systems and to date, there are neurological, respiratory, gastrointestinal, ophthalmological and endocrine consequences reported. A small number of patients have had reported renal and cardiovascular congenital abnormalities.

The commonest reported neurological consequence is neurodevelopmental delay, seizures and hypotonia. The majority of children have global developmental delay with severely delayed motor development and lack of speech. The majority of children are unable to ambulate independently or speak. In those that can ambulate, the gait is often unsteady and broad based. The seizure types, onset and treatment efficacy are very variable and can be refractory to treatment. Hypotonia is often present from birth and is likely a contributing factor in feeding, breathing and developmental difficulties. Various movement disorders including dystonia and dyskinesia have been identified. There are also reports of stereotypical hand movements and peripheral neuropathy. Some patients have evidence of delayed myelination on MRI.

Gastrointestinal symptoms include constipation, dysphagia, reflux and feeding difficulties.
Respiratory problems include hypoventilation and obstructive and centrally mediated apnoea. Many of these cases are reported in the neonatal period and the majority show improvement in infancy. It is worth noting that additional respiratory support may be required in acute illnesses.
Ophthalmological manifestations include refraction errors, exophoria, cortical visual impairment, strabismus and nystagmus.
Skeletal abnormalities include scoliosis, hyperlaxity and hip dysplasia.
There are also cases of associated congenital cardiac disease, congenital urogenital malformations, kidney stones, vitamin D deficiency, osteopenia, pubertal abnormalities, aberrant hormone production and short stature. However the prevalence and significance of these require further research.