Targeted gene under study

 BLM (#OMIM: *604610 = RECQL3), CENPJ (*609279), CEP135 (*611423), CEP152 (*613529), LIG4 (*601837), PCNT (*605925) and PLK4 (*605031)
Aim: Better delineation of clinical and neuroradiological phenotypes

  • Growth parameters
  • Brain MRI characteristic
  • Neuropsychological study based on WPPSI/WAIS/WISC or tests Vineland Adaptive Behavior Scales


Primary Microcephalic Dwarfisms (PMDs) are rare autosomal recessive diseases defined by a reduction in brain and body size. PMDs include MOPDII, Seckel, Bloom and LIG4 syndromes caused by pathogenic variants in PCNT, CEP152, CEP135, CENPJ, PLK4, BLM, LIG4, the most frequent, and some others. 
436 patients carrying variants in PCNT, CEP152, CEP135, CENPJ, PLK4, BLM and LIG4 have been described. However, even if height and OFC are quite well completed, brain imaging, neurodevelopmental and cognitive outcome of these patients are still lacking and it is unfortunate that only 4.5% of the patients were assessed by neuropsychological tests.
To better understand the natural history of these patients and to be able to precise the genetic counselling of this condition, we would like to collect OFC and height parameters, brain MRI data, motor, language and cognitive development of children or adults patients carrying PCNT, CEP152, CEP135, CENPJ, PLK4, BLM pathogenic variants and to add them to the 18 patients included in the medical thesis of Dr. Hassina Hachour. 
Our aim is to better understand the neurodevelopment and the autonomy in adulthood of these patients, to be able to explain their long term prognosis and to precise the genetic counselling.

Coordinating clinicians/researchers

Pr. Sandrine PASSEMARD –
Dr. Hassina HACHOUR – 


Hôpital Robert Debré, Université Paris Cité, Paris, France

Specific requirements beyond clinical data and genotype data sharing:

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