Novel clinical features and pleiotropic effect in three unrelated patients with LMNA variant

Rare variation in LMNA underlies polycystic ovary syndrome (PCOS) pathogenesis in two independent cohorts

CONTEXT

Polycystic ovary syndrome (PCOS) is a common, heritable endocrinopathy that is a common cause of anovulatory infertility in reproductive age women. Variants in LMNA cause partial lipodystrophy, a syndrome with overlapping features to PCOS.

OBJECTIVE

We tested the hypothesis that rare variation in LMNA contributes to PCOS pathogenesis and selects a lipodystrophy-like subtype of PCOS.

DESIGN, SETTING, AND PARTICIPANTS

We sequenced LMNA by targeted sequencing a discovery cohort of 811 PCOS patients and 164 healthy controls. We then analyzed LMNA from whole-exome sequencing (WES) of a replication cohort of 718 PCOS patients and 281 healthy controls.

MAIN OUTCOME MEASURES

Variation in the LMNA gene, hormone and lipid profiles of participants.

RESULTS

In the discovery cohort, we identified 8 missense variants in 15/811 cases, and 1 variant in 1/172 reproductively healthy controls. There is strong evidence for association between the variants and PCOS compared to gnomAD non-Finnish European population controls (χ2=17, p=3.7x10-5, OR=2.9). In the replication cohort, we identified 11 unique variants in 15/718 cases, and 1 variant in 281 reproductively healthy controls. Again, there is strong evidence for association with population controls (χ2=30.5, p=3.4x10-8, OR= 4.0). In both the discovery and replication cohorts, variants in LMNA identify women with PCOS with high triglycerides and extreme insulin resistance.

CONCLUSIONS

Rare missense variation in LMNA is reproducibly associated with PCOS and identifies some individuals with lipodystrophy-like features. The overlap between this PCOS phenotype and genetic partial lipodystrophy syndromes warrants further investigation into additional lipodystrophy genes and their potential in PCOS etiology.

Deciphering the Clinical Presentations in LMNA-related Lipodystrophy: Report of 115 Cases and a Systematic Review

CONTEXT

Lipodystrophy syndromes are a heterogeneous group of rare genetic or acquired disorders characterized by generalized or partial loss of adipose tissue. LMNA-related lipodystrophy syndromes are classified based on the severity and distribution of adipose tissue loss.

OBJECTIVE

We aimed to annotate all clinical and metabolic features of patients with lipodystrophy syndromes carrying pathogenic LMNA variants and assess potential genotype-phenotype relationships.

METHODS

We retrospectively reviewed and analyzed all our cases (n = 115) and all published cases (n = 379) curated from 94 studies in the literature.

RESULTS

The study included 494 patients. The most common variants in our study, R482Q and R482W, were associated with similar metabolic characteristics and complications though those with the R482W variant were younger (aged 33 [24] years vs 44 [25] years; P < .001), had an earlier diabetes diagnosis (aged 27 [18] vs 40 [17] years; P < .001) and had lower body mass index levels (24 [5] vs 25 [4]; P = .037). Dyslipidemia was the earliest biochemical evidence described in 83% of all patients at a median age of 26 (10) years, while diabetes was reported in 61% of cases. Among 39 patients with an episode of acute pancreatitis, the median age at acute pancreatitis diagnosis was 20 (17) years. Patients who were reported to have diabetes had 3.2 times, while those with hypertriglyceridemia had 12.0 times, the odds of having pancreatitis compared to those who did not.

CONCLUSION

This study reports the largest number of patients with LMNA-related lipodystrophy syndromes to date. Our report helps to quantify the prevalence of the known and rare complications associated with different phenotypes and serves as a comprehensive catalog of all known cases.