Targeted gene/syndrome under study

Infantile hypotonia, with psychomotor retardation and characteristic facies 1 (IHPRF1, OMIM # 615419)


Infantile hypotonia, with psychomotor retardation and characteristic facies 1 (IHPRF1; OMIM #615419), is a severe autosomal recessive disorder caused by biallelic deleterious variants in NALCN gene (OMIM #611549). Affected individuals show psychomotor delay and hypotonia, usually severe, profound intellectual disability, and failure to thrive. Additional manifestations include microcephaly, progressive peripheral spasticity, bilateral strabismus and nystagmus, constipation, rhythmic breathing abnormalities and variable dysmorphic facial features. We retrieved in a patient with classic phenotype a unique finding of urinary glucotetrasaccharides elevation, whose levels are usually tested as sensitive biomarker of muscle involvement and/or to monitor the therapeutic response to enzyme replacement therapy i.e., in other glycogen storage diseases. This study aims to expand the existing genotype-phenotype correlation of this rare neurodevelopmental disorder and, by collecting urinary samples from other IHPRF1 affected individuals, to verify if urinary glucotetrasaccharides could represent a reliable biomarker also in NALCN-related disorders. We kindly ask you to contact us if you have patients with IHPRF1 to collect clinical data and to organize the resampling of urine specimen that will be analysed in our laboratories.

Coordinating clinicians/researchers

Dr Davide VECCHIO –

Dr Filippo Maria PANFILI –

Dr Michela SEMERARO –


Rare Diseases and Medical Genetics Unit & Division of Metabolic Diseases.

Bambino Gesù Children’s Hospital, IRCSS, Rome, Italy.

Specific requirements beyond clinical data and genotype data sharing:

  • Re-analysis of DNA samples: No
  • Resampling of patients: Yes
  • Linked to a translational/basic research project: Yes