Progressively decreasing plasma high-density lipoprotein cholesterol levels preceding diagnosis of smoldering myeloma.

We report a case of disappearing high-density lipoprotein (HDL) syndrome caused by oxidative modification of HDL and by autoantibodies against modified HDL, with subsequent diagnosis of myeloma. An elderly Caucasian man had normal lipid levels with HDL cholesterol (HDL-C) levels in the upper 70 mg/dL range from 1999 to 2003. In 2003, his HDL-C levels began to progressively fall, and by 2011, they were undetectable (<5 mg/dL) when measured with a Beckman Synchron LX auto analyzer. Analyses of the plasma sample from 2011 using ultracentrifugation (Vertical Auto Profile), nuclear magnetic resonance, and Ace EXCEL auto analyzer have shown that HDL-C levels were easily detectable (47-54 mg/dL), although reduced compared with his pre-2003 values. Analyses of his plasma sample from 2011 also showed the presence of lipid-adducted apolipoprotein A1 (apoA1) and high titer of antibodies against the adducted apoA1. Interestingly, a negative correlation between HDL-C levels and the titer of antibodies against apoA1 adducts was found in the control cohort. Finally, we show that in the mouse system, an antibody against apoA1 increases the clearance of HDL from plasma. This case of smoldering myeloma preceded by acquired, severe HDL-C deficiency, likely because of oxidative modifications of the HDL protein leading to the formation of autoantibodies, interference with clinical measurement of HDL-C, and increased plasma clearance of HDL, adds to the list of diagnostic considerations for unexplained HDL-C decreases over time.

A case of severe acquired hypertriglyceridemia in a 7-year-old girl.

We report a case of severe type I hyperlipoproteinemia caused by autoimmunity against lipoprotein lipase (LPL) in the context of presymptomatic Sjögren's syndrome. A 7-year-old mixed race (Caucasian/African American) girl was admitted to the intensive care unit at Vanderbilt Children's Hospital with acute pancreatitis and shock. She was previously healthy aside from asthma and history of Hashimoto's thyroiditis. Admission triglycerides (TGs) were 2191 mg/dL but returned to normal during the hospital stay and in the absence of food intake. At discharge, she was placed on a low-fat, low-sugar diet. She did not respond to fibrates, prescription fish oil, metformin, or orlistat, and during the following 2 years, she was hospitalized several times with recurrent pancreatitis. Except for a heterozygous mutation in the promoter region of LPL, predicted to have no clinical significance, she had no further mutations in genes known to affect TG metabolism and to cause inherited type I hyperlipoproteinemia, such as APOA5, APOC2, GPIHBP1, or LMF1. When her TG levels normalized after incidental use of prednisone, an autoimmune mechanism was suspected. Immunoblot analyses showed the presence of autoantibodies to LPL in the patient's plasma. Autoantibodies to LPL decreased by 37% while patient was on prednisone, and by 68% as she subsequently transitioned to hydroxychloroquine monotherapy. While on hydroxychloroquine, she underwent a supervised high-fat meal challenge and showed normal ability to metabolize TG. For the past 3 years and 6 months, she has had TG consistently <250 mg/dL, and no symptoms of, or readmissions for, pancreatitis.

Sex-Specific Parental Effects on Offspring Lipid Levels.

BACKGROUND: Plasma lipid levels are highly heritable traits, but known genetic loci can only explain a small portion of their heritability. METHODS AND RESULTS: In this study, we analyzed the role of parental levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TGs) in explaining the values of the corresponding traits in adult offspring. We also evaluated the contribution of nongenetic factors that influence lipid traits (age, body mass index, smoking, medications, and menopause) alone and in combination with variability at the genetic loci known to associate with TC, LDL-C, HDL-C, and TG levels. We performed comparisons among different sex-specific regression models in 416 families from the Framingham Heart Study and 304 from the SardiNIA cohort. Models including parental lipid levels explain significantly more of the trait variation than models without these measures, explaining up to ≈39% of the total trait variation. Of this variation, the parent-of-origin effect explains as much as ≈15% and it does so in a sex-specific way. This observation is not owing to shared environment, given that spouse-pair correlations were negligible (<1.5% explained variation in all cases) and is distinct from previous genetic and acquired factors that are known to influence serum lipid levels. CONCLUSIONS: These findings support the concept that unknown genetic and epigenetic contributors are responsible for most of the heritable component of the plasma lipid phenotype, and that, at present, the clinical utility of knowing age-matched parental lipid levels in assessing risk of dyslipidemia supersedes individual locus effects. Our results support the clinical utility of knowing parental lipid levels in assessing future risk of dyslipidemia.

Oral retinoids and plasma lipids.

Retinoids and rexinoids are prescribed for conditions ranging from acne vulgaris to hyperkeratosis to cutaneous T cell lymphoma. Dyslipidemia is a frequent consequence of the use of these drugs, with more than one-third of patients manifesting aberrations in triglyceride (TG) levels. The efficacy of retinoic acid derivatives is linked to their influence on lipid metabolism in the skin, which can impair systemic lipid trafficking and metabolism in some patients. Thus, baseline screening for preexisting dyslipidemia and regular follow-up lipid panels are mandated, especially when powerful agents such as bexarotene are used. Dietary modification, increased physical activity, and weight management are the cornerstones of initial management for mild hypertriglyceridemia, which is a contributor to cardiovascular risk. More severe impairments (fasting TG > 500 mg/dL) warrant pharmacologic interventions early on to reduce the risk of pancreatitis. Retinoic acid derivative action, lipid metabolism, and treatment of incident dyslipidemias are reviewed to empower prescribers in management of adverse lipid effects.

Validation of the diabetes numeracy test with adolescents with type 1 diabetes.

There is currently a lack of valid instruments to measure adolescent diabetes numeracy. The Diabetes Numeracy Test (DNT) was adapted for type 1 diabetes and was administered to 2 samples of adolescents. Sample 1 was administered the 39-item version of the DNT (DNT-39) with measures of self-management, responsibility, reading, and glycemic control (A1C). Sample 2 was administered the 14-item version of the DNT (DNT-14) with measures of self-management, responsibility, problem solving, and A1C. Both versions of the DNT showed adequate internal reliability. In Sample 1, the DNT-39 and DNT-14 were related (r = .87, p = .001), and both DNT versions were related to parent education (for DNT-14, r = .31, p = .02; for DNT-39, r = .29, p = .03) and reading (for DNT-14, r = .36, p = .005; for DNT-39, r = .40, p = .001). In Sample 2, the DNT-14 was related to A1C (r = -.29, p = .001), reading skills (r = .36, p = .005), diabetes problem solving (r = .27, p = .02), adolescent age (r = .19, p = .03), and parent education (r = .31, p = .02). In combined analyses, 75% of items were answered correctly on the DNT-14 (range = 7-100), and performance was associated with age (r = .19, p = .03), pump use (r = .33 p = .001), and A1C (r = -.29, p = .001). The DNT-14 is a feasible, reliable, and valid numeracy assessment that indicated adolescents with type 1 diabetes have numeracy deficits that may affect their glycemic control.

Delayed diagnosis of hypothyroidism following excision of a thyroglossal duct cyst.

Thyroglossal duct cysts can contain ectopic thyroid tissue, and in some cases this tissue may be the only functional thyroid gland. We present the case of a 6-year-old girl with delayed diagnosis of iatrogenic hypothyroidism that developed after excision of a thyroglossal duct cyst.