Non-invasive prenatal diagnosis (NIPD) of cystic fibrosis: an optimized protocol using MEMO fluorescent PCR to detect the p.Phe508del mutation

C. Guissart (1, 2, 3) , C. Dubucs (1, 2) , C. Raynal (1, 2, 3) , A. Girardet (1, 2, 3) , F. Tran Mau Them (1, 2) , V. Debant (1, 2) , C. Rouzier (4) , A. Boureau-Wirth (4) , E. Haquet (1) , J. Puechberty (1) , E. Bieth (5) , D. Dupin Deguine (5) , P. Khau van Kien (6) , M. Brechard (7) , V. Pritchard , Michel Koenig (1, 2, 3) , M. Claustres (1, 2, 3) , M.C. Vincent (1, 2, 3)

1 Département de génétique médicale, maladies rares et médecine personnalisée [CHRU Montpellier]
2 AIDMP - Aide à la Décision pour une Médecine Personnalisé - Laboratoire de Biostatistique, Epidémiologie et Recherche Clinique - EA 2415
3 LGMR - Laboratoire de génétique des maladies rares. Pathologie moleculaire, etudes fonctionnelles et banque de données génétiques
4 Dpt génétique médicale [CHU Nice]
5 CHU Toulouse - Centre Hospitalier Universitaire de Toulouse
6 CHU Nîmes - Centre Hospitalier Universitaire de Nîmes
7 Hôpital Saint-Joseph [Marseille]

BACKGROUND:Analysis of cell-free foetal DNA (cff-DNA) in maternal plasma is very promising for early diagnosis of monogenic diseases; in particular, cystic fibrosis (CF). However, NIPD of single-gene disorders has been limited by the availability of suitable technical platforms and the need to set up patient or disease-specific custom-made approaches.METHODS:To make research applications more readily accessible to the clinic, we offer a simple assay combining two independent methods to determine the presence or absence of paternally inherited foetal allele p.Phe508del (the most frequent mutation in CF patients worldwide). The first method detects the presence or absence of a p.Phe508del allele by Mutant Enrichment with 3'-Modified Oligonucleotide PCR coupled to Fragment Length Analysis (MEMO-PCR-FLA). The second method detects the p.Phe508del allele with classical Multiplex Fluorescent PCR including five intragenic and extragenic STR markers of the CFTR locus and a specific SRY sequence.RESULTS:We collected 24 plasma samples from 23 women carrying foetuses at risk for CF and tested each sample using both methods. Our new procedures were successfully applied to 10 couples where fathers carried the p.Phe508del mutation and mothers were carrying a different mutation in the CFTR gene. These simple tests provided clear positive or negative results from the maternal plasma of the pregnant women. We confirmed the presence of cff-DNA in the studied samples by the identification of a tri-allelic DNA profile using a miniSTR kit. All results were correlated with chorionic villus sampling or amniocentesis analyses.CONCLUSIONS:This NIPD approach, easily set up in any clinical laboratory where prenatal diagnosis is routinely performed, offers many advantages over current methods: it is simple, rapid, and cost-effective. It opens up the possibility for testing a large number of couples with offspring at risk for CF.

Mots clés: Cystic fibrosis; MEMO-PCR; NIPD; Non-invasive prenatal diagnosis; cff-DNA; p.Phe508del

Domaines: Pneumologie et système respiratoire

C. Guissart, C. Dubucs, C. Raynal, A. Girardet, F. Tran Mau Them, et al.. Non-invasive prenatal diagnosis (NIPD) of cystic fibrosis: an optimized protocol using MEMO fluorescent PCR to detect the p.Phe508del mutation. Journal of Cystic Fibrosis, 2017, 16 (2), pp.198 - 206. ⟨10.1016/j.jcf.2016.12.011⟩. ⟨hal-01792996⟩