Dunnigan-type familial partial lipodystrophy (FPLD2) is a rare genetic disease associated with loss of subcutaneous adipose tissue and accompanying metabolic involvement such as diabetes, hyperlipidemia, and hepatosteatosis. We aimed to present a rare family with FPLD2 caused by an atypical Lamin A/C gene (LMNA) mutation.
The proband of this family was a 43-year-old female patient who was diagnosed with FPLD2 caused by a heterozygous missense mutation, R582H (c.1745G→A) in exon 11. Here, we report her prospective 8-year follow-up as regard to metabolic complications and end-organ abnormalities.
Due to adipose tissue dysfunction, she developed type 2 diabetes, hypertriglyceridemia, and hepatosteatosis at her thirties. In contrast to many patients with typical FPLD2, her diabetes was well regulated by metformin monotherapy. Lifestyle management, dietary modifications, and fenofibrate monotherapy successfully treated the hypertriglyceridemia. No complication of diabetes has developed. Cardiac and neurological regular assessments were normal. Her father was also diagnosed with FPLD2 caused by the same point mutation. Similarly, his diabetes and hypertriglyceridemia could be easily managed by lifestyle modifications, metformin, and fenofibrate and no end-organ complication was observed.
LMNA undergoes alternative splicing to produce two nuclear laminar proteins - lamin A and C. Multiple missense mutations associated with FPLD2, most of which are located in exon 8 at the codon position 482, have been reported. The missense mutation in our patient was also associated with FPLD2, however, the clinical reflection was somehow milder. This could be explained by the fact that exon 11 mutation affects only lamin A, unlike exon 8 mutation which affects both lamin A and C proteins.