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P59 Clinical diversity in 22q11.2 microdeletion syndrome & difficulties in diagnoses using only fluroscence in situ hybridisation (fish)
  1. Hemma Chauhan1,
  2. Vasilica Plaiasu2,
  3. Ozunu Diana2,
  4. Motei Gabriela2
  1. 1University of Medicine and Pharmacy ‘Carol Davila’ Bucharest, Romania
  2. 2Paediatric Genetics; Regional Centre of Medical Genetics ‘Alessandrescu-Rusescu’ (INSMC); Bucharest; Romania

Abstract

Background and Aims 22q11 Microdeletion syndrome is the most common microdeletion syndrome and the second most common genetic syndrome, but due to its vast range of clinical features varying in severity it commonly goes undiagnosed. As the symptoms are so varied, different clusters of features were named separately; such as Cayler cardiofacial syndrome, conotruncal anomaly face syndrome, DiGeorge syndrome and velocardiofacial syndrome. The genetics behind these syndromes were later identified and as such they all belong to a single syndrome: 22q11 Microdeletion syndrome. Our aim is to highlight the clinical diversity in patients with 22q11.2 microdeletion syndrome and identify the difficulties in providing a patient with a diagnosis.

Methods A retrospective cross-sectional study of 74 suspected 22q11.2 microdeletion patients between 2010–2016. Conventional karyotyping along with fluorescence in situ hybridisation (FISH) using either the TUPLE1 or TBX1 probe were performed for the suspected cases with 22q11.2 microdeletion syndrome.

Results All of the patients presented with a normal karyotype. 10 out of 74 patients tested positive for 22q11.2 microdeletion syndrome using FISH technique. Out of the 10 patients, 50% presented a cardiac abnormality, 50% with dysmorphic features, 30% with renal abnormalities, 20% with a cleft palate, 10% with a hypoplastic thymus and 10% with developmental delay. The remaining 64 patients who tested negative presented similar clinical findings and will have to continue investigations using other methods for testing.

Conclusions There is no common presentation of 22q11.2 microdeletion syndrome. Out of the 10 positive FISH technique patients there is no common tie, illustrating the difficulties in suspecting the syndrome initially. The diagnosis is only achieved in Romania through FISH analysis, leaving 64 suspected patients who presented with similar clinical features without a diagnosis. Further research is needed into simple, affordable tests to diagnose 22q11.2 microdeletion syndrome.

  • 22q11.2 microdeletion syndrome
  • DiGeorge syndrome
  • velocardiofacial syndrome
  • FISH

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