MON-LB120 MODY3 With Insulin Coding Gene Mutation and Craniofacial Microsomia: A Case Report

Background: Maturity onset diabetes in young 3 (MODY 3) is caused by mutation of the hepatic nuclear factor 1 alpha (HNF-1A) gene. Craniofacial macrosomia (CFM) is associated with an abnormal development of craniofacial structures during the embryonic period. Maternal diabetes and genetic predisposition have been associated with CFM(1). There are rare reports about an association of MODY 3 and CFM. Clinical case: An 11-year-old male patient presented with right side CFM (mild mandibular hypoplasia, internal auditory canal absence, severe pinna hypoplasia, abnormal orbital size and location, O3.M0.E3.N0.S0(2)) noted at 8 months of age. Preoperative examination revealed A1c at 10.9%. After short term intensive insulin therapy, he had standard bread meal test: fasting glucose 8.11 mmol/L, insulin 13.9 mIU/L (3-25), C-peptide 1.25 ng/ml (0.81-3.85); 1 hour glucose 10.05 mmol/L, insulin 27 mIU/L, C-peptide 2.42 ng/ml; 2 hour glucose 8.17 mmol/L, insulin 16.09 mIU/L, C-peptide 2.11 ng/ml. GADA, IAA and ICA were negative. The mother was diagnosed diabetes at age 27years, when the patient was 8-month-old, and received insulin therapy. The mother was blind by age 35years due to diabetic retinopathy and died of DKA at 38-years-old. The patient’s 16-year-old brother had left side CFM (O2.M1.E2.N0.S0) and his OGTT was normal. The father was diagnosed with impaired glucose tolerance. The family had whole genome sequencing by Sanger technique, and resequenced the mutation with side primers. The CGA to CAA mutation was present at the 686 loci of exon 3 of HNF1A gene in the patient and mother. The HNF1A exon 3 mutation of CGA to CAA resulted in the change of arginine to glutamine which by the HGMA database is recognized as a reported MODY3 gene mutation. There was a mutation of G to A in the 4 loci of exon 1 of the insulin coding region in chromosome 11 in both the patient and elder brother. Neither elder brother nor father had the CGA mutation of HNF1A. Conclusion: There has not been a previous report of a relationship between HNF1A and CFM. In this case, the elder brother had CFM without a HNF1A mutation which does not support a connection between CFM and HNF1A. The two brothers both had CFM and insulin coding gene mutations which would represent a new association not previously described. Further testing is needed to confirm a relationship between the two. Reference: 1. Chen Q, Zhao Y, Shen G, Dai J. Etiology and Pathogenesis of Hemifacial Microsomia. J Dent Res 2018; 97(12): 1297-305. 2. Gougoutas AJ, Singh DJ, Low DW, Bartlett SP. Hemifacial microsomia: clinical features and pictographic representations of the OMENS classification system. Plast Reconstr Surg 2007; 120(7): 112e-20e.