Novel Homozygous Variants in CIDEC and WRN in a Young Female with Lipodystrophy and Thyroid Cancer.

Autosomal recessive familial partial lipodystrophy type 5 (FPLD5) due to a homozygous NP_001186481.1; p.E186* CIDEC variant has previously been reported in a 19-year-old female with diabetes mellitus, hypertriglyceridemia, and hepatic steatosis. Now, we report an 18-year-old Hispanic female who presented with FPL, along with hirsutism, acanthosis nigricans, and marked insulin resistance, and was found to have an extremely rare homozygous variant in CIDEC (NM_001199623.2:c.224G>T; NP_001186552.1; p.Ser75Ile) by whole exome sequencing. She also harbored a novel homozygous variant in WRN (NM_000553.4:c.1856T>G; NP_000544; p.Leu619Arg). Both serine 75 of the CIDEC protein and leucine 619 of the WRN protein were well conserved across species. She developed an invasive papillary thyroid carcinoma at the age of 17 years. Our report confirms the previously reported association of the biallelic CIDEC variant with the FPL phenotype and also highlights the extremely rare possibility of co-occurrence of FPLD5 with thyroid cancer, a clinical feature of Werner syndrome. Thus, our patient may not only need surveillance for the metabolic complications of FPLD5, such as diabetes, hypertriglyceridemia, and hepatic steatosis, but also for WRN-associated neoplasms and features of premature aging.