First evidence of Smith-Magenis syndrome in mother and daughter due to a novel RAI mutation


Smith-Magenis syndrome (SMS) is a complex genetic disorder caused by interstitial 17p11.2 deletions encompassing multiple genes, including the retinoic acid induced 1 gene-RAI1-or mutations in RAI1 itself. The clinical spectrum includes developmental delay, cognitive impairment, and behavioral abnormalities, with distinctive physical features that become more evident with age. No patients have been reported to have had offspring. We here describe a girl with developmental delay, mainly compromising the speech area, and her mother with mild intellectual disabilities and minor dysmorphic features. Both had sleep disturbance and attention deficit disorder, but no other atypical behaviors have been reported. In both, CGH-array analysis detected a 15q13.3 interstitial duplication, encompassing CHRNA7. However, the same duplication has been observed in several, apparently healthy, maternal relatives. We, thus, performed a whole exome sequencing analysis, which detected a frameshift mutation in RAI1, de novo in the mother, and transmitted to her daughter. No other family members carried this mutation. This is the first report of an SMS patient having offspring. Our experience confirms the importance of searching for alternative causative genetic mechanisms in case of confounding/inconclusive findings such as a CGH-array result of uncertain significance. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Authors Acquaviva F, Sana ME, Della Monica M, Pinelli M, Postorivo D, Fontana P, Falco MT, Nardone AM, Lonardo F, Iascone M, Scarano G
Journal American journal of medical genetics. Part A
Publication Date 2017 Jan;173(1):231-238
PubMed 27683195
DOI 10.1002/ajmg.a.37989

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