Histidinaemia. Part III: Impact; a prospective study.

Area of Science:

• Biochemistry
• Genetics
• Neurodevelopmental Disorders

Background:

• Histidinaemia is an inborn error of histidine metabolism.
• Newborn screening programs identify individuals with histidinaemia.
• The long-term developmental impact of histidinaemia remains incompletely understood.

Purpose of the Study:

• To prospectively evaluate the neurodevelopmental outcomes of individuals with histidinaemia identified via newborn screening.
• To correlate biochemical phenotype with clinical and cognitive assessments.
• To determine if histidinaemia represents a disadaptive phenotype.

Main Methods:

• Prospective study of 21 probands and siblings with histidinaemia from 16 families.
• Subjects ascertained through newborn screening and confirmed biochemically.
• Evaluated cognitive function (IQ, Visual-Motor Integration), academic achievement (Wide Range Achievement Test), and psychological history.
• Medical history, including pregnancy and developmental milestones, was reviewed.
• Findings correlated with biochemical phenotype.

Main Results:

• Central nervous system (CNS) development was normal in histidinaemic subjects, with mean and distribution of scores falling within expected ranges.
• No correlation was found between outlier cognitive values and the degree of histidinaemia.
• No subjects received dietary treatment for histidinaemia.

Conclusions:

• Histidinaemia detected by newborn screening is a non-disadaptive phenotype.
• Individuals with histidinaemia identified early do not exhibit significant neurodevelopmental impairments.
• Early identification and monitoring without specific dietary intervention appear to yield normal developmental trajectories.