Primary hepatocellular adenoma due to biallelic HNF1A mutations and its co-occurrence with MODY 3: case-report and review of the literature

Abstract

Purpose: Maturity-onset diabetes of the young type 3 (MODY 3) is a consequence of heterozygous germline mutations in HNF1A, and a subtype of hepatocellular adenoma (HCA) is caused by biallelic somatic HNF1A mutations; rare HCA may be related to MODY 3. This study aimed to investigate the cosegregation of HNF1A mutations with diabetes and HCA in two families.

Methods: Two patients suffering from HCA and diabetes were screened for HNF1A germline and somatic mutations using direct sequence analysis and methylation-specific multiplex-ligation-dependent probe amplification (MS-MLPA) assay. Further, we screened eight relatives in the two independent families for diabetes, HCA and HNF1A variants. Additionally, we reviewed the literature concerning the phenotypes of MODY 3 and HCA at the background of HNF1A mutations.

Results: Here we reported two families (a total of six relatives) with two missense germline mutations of HNF1A identified initially using direct sequence analysis (c.686G>A in family A and c.526 + 1G>A in family B). Somatic deletion of the second allele of HNF1A was found in liver tumor tissues in both probands who were diagnosed with HCA. There are a total of ten cases of both MODY 3 and HCA phenotypes reported in the literature to date; incomplete penetrance for HCA was observed, and all the patients with HCA developed diabetes. The onset of diabetes and HCA was highly variable, the treatment of diabetes varied from diet to insulin, and the clinical expression of HCA ranged from silent to hemorrhage. Further, the severity of diabetes mellitus was not related to the occurrence of HCA.

Conclusions: This study describes the association of HCA and MODY 3 at the background of HNF1A mutations and highlights the importance of screening for HCA in MODY 3 families to avoid the possibility of severe complications. Further, the current study indicated that there may be a special mutational spectrum of HNF1A correlated with HCA in MODY 3 families.

Keywords: HNF1A; Hepatocellular adenoma; MODY 3.

Fig. 1

Pedigree of families of proband 1 (a) and proband 2 (b). Squares represent male family members, while circles represent female family members. The black symbol on the left represents individuals with diabetes, the black symbol on the right represents individuals with hepatocellular adenoma, and the blank symbols represent normal individuals. Arrows indicate probands in the families (a, IIIa; b, IVa). Variant carrier status is presented as N: Normal allele and M: Mutation. The sequence data displayed heterozygous mutations in HNF1A (c.686G>A, p.R229Q in proband 1; c.526 + 1G>A in proband 2). The second line under the symbols corresponds to the onset age of diabetes

Fig. 2

The sequencing chromatogram and position of the mutation in HNF1A gene. Arrows indicate the changed nucleotide

Fig. 3

Computed tomography (CT) scans of the two probands. CT scans taken on the preoperative day (a: proband 1; b: proband 2). The size of the tumors of proband 1 was 60 mm × 57 mm × 48 mm (52 HU), and that of proband 2 was 47 mm × 42 mm (48 HU) (arrowhead)

Fig. 4

Histological characteristics of the hepatocellular adenoma. a proband 1: CD34 (part+), CK19 (−), CK7 (scattered+), Ki-67 (index 5%), β-catenin (membrane+), AFP (−), GPC-3 (−), and reticulum fiber (+). b proband 2: GPC-3 (−), CK7 (−), CEA (−), IMP3 (−), Ki-67 (index 2%), CD34 (vessel+), CAM5.2 (+), AFP (−), Hepatocyte (+), β-catenin (membrane+), and CK19 (−)

Fig. 5

Results of the MS-MLPA in the region of HNF1A in proband 1 (a) and proband 2 (b). The methylation-specific multiplex-ligation-dependent probe amplification (MS-MLPA) assay was performed with SALSA MLPA Probemix P241-E1 MODY Mix 1 (MRC-Holland, Amsterdam, The Netherlands). The P241-E1 MODY Mix 1 Probemix contains 52 MLPA probes with amplification products between 130 and 500 nt. It contains probes for the HNF4A, GCK, HNF1A, and HNF1B genes and is therefore specific for MODY 1, 2, 3, and 5. For the HNF4A gene, 12 probes are included, furthermore 11 for the GCK gene, 11 for the HNF1A gene, and 10 for the HNF1B gene are included. In addition, eight reference probes are included in this probe mix. The identity of the genes detected by the reference probes is available online (www.mlpa.com). The validation experiment should result in a standard deviation <0.10 for all probes over the experiment (0.08 for proband 1, 0.05 for proband 2). The threshold for chromosomal abnormalities was established as follows: the lower limit was 0.7 for deletion and the upper limit was 1.33 for duplication. Abnormal values were plotted outside the threshold line. Heterozygous deletion mutation in exons 1–10 of HNF1A gene was found in both proband 1 and proband 2