Alterations in the brain adenosine metabolism cause behavioral and neurological impairment in ADA-deficient mice and patients.

Adenosine Deaminase (ADA) deficiency is an autosomal recessive variant of severe combined immunodeficiency (SCID) caused by systemic accumulation of ADA substrates. Neurological and behavioral abnormalities observed in ADA-SCID patients surviving after stem cell transplantation or gene therapy represent an unresolved enigma in the field. We found significant neurological and cognitive alterations in untreated ADA-SCID patients as well as in two groups of patients after short- and long-term enzyme replacement therapy with PEG-ADA. These included motor dysfunction, EEG alterations, sensorineural hypoacusia, white matter and ventricular alterations in MRI as well as a low mental development index or IQ. Ada-deficient mice were significantly less active and showed anxiety-like behavior. Molecular and metabolic analyses showed that this phenotype coincides with metabolic alterations and aberrant adenosine receptor signaling. PEG-ADA treatment corrected metabolic adenosine-based alterations, but not cellular and signaling defects, indicating an intrinsic nature of the neurological and behavioral phenotype in ADA deficiency.

Paths of cognitive and language development in healthy preterm infants.

OBJECTIVE: Despite the presence of many studies on difficulties related to premature birth, findings on developmental outcomes are heterogeneous. This could be explained from a biological and environmental point of view, but also from a methodological one. The aims of this study were as follows: assess cognitive and linguistic performance using the BSID-III in a population of healthy preterm infants at 24 and 36 months (corrected age); analyze whether the correction for prematurity should be applied, decide when to stop using corrected age and evaluate possible improvements between 24 and 36 months. METHODS: Developmental outcome was assessed at 24 and 36 months (corrected age) with the BSID-III in 75 healthy preterm (GA=32.5±1.97; BW=1631.55±453.92) and 69 term-born children (GA=39.77±1.00; BW=3298.95±457.27). RESULTS: Preterm infants had significantly lower scores than those of term infants in Cognitive (COG) and Language (LANG REC, LANG EC) scales of the BSID-III at both 24 and 36 months, considering both corrected (CA) and chronological (UCA) age. At 24 months, significant differences between corrected and chronological scores were found for each BSID-III scale, while at 36 months, significant differences between corrected and chronological scores were found for LANG scales. Only the scores in the COG scale were statistically different between 24 and 36 months (F=4.894, P=0.009, η(2)=0.075). Considering only the preterm sample at 24 months, the differences between CA and UCA scores in the COG scale were significantly correlated to GA (p=0.000) and days in hospital (p=0.002;), while differences between CA and UCA scores in the LANG ESP scale were significantly correlated to GA (p=0.010), days in hospital (p=0.001), and birth weight (p=0.007). At 36 months, no significant correlations were found. CONCLUSIONS: Preterm birth is followed by poorer cognitive and language outcomes during infancy than full-term birth. Age correction of prematurity is useful if the child is under 2 years of age; however, our findings raise concerns about the need for age correction, considering that at later ages, healthy preterm children have a higher rate of developmental delay compared with term infants. With regard to cognitive development, preterm children seem to recover from their initial disadvantage; however, with regard to linguistic development, data confirm that preterm infants are at risk for language difficulties.