Papulonodular dermal mucinosis in systemic lupus erythematosus.

A 38-year-old woman with systemic lupus erythematosus presented to the dermatology department with diffuse nodules and plaques on her face, trunk and extremities. A lesional biopsy revealed large dermal mucin deposits. Papulonodular dermal mucinosis is characterized histologically by diffuse dermal mucin without the classic epidermal or inflammatory changes seen in lupus erythematosus (LE). This rare variant of LE should be distinguished from other cutaneous mucinoses.

BRCA1 maps proximal to D17S579 on chromosome 17q21 by genetic analysis.

Previous studies have demonstrated linkage between early-onset breast cancer and ovarian cancer and genetic markers on chromosome 17q21. These markers define the location of a gene (BRCA1) which appears to be inherited as an autosomal dominant susceptibility allele. We analyzed five families with multiple affected individuals for evidence of linkage to the BRCA1 region. Two of the five families appear to be linked to BRCA1. One apparently linked family contains critical recombinants, suggesting that the gene is proximal to the marker D17S579 (Mfd188). These findings are consistent with the maximum-likelihood position estimated by the Breast Cancer Linkage Consortium and with recombination events detected in other linked families. Linkage analysis was greatly aided by PCR-based analysis of paraffin-embedded normal breast tissue from deceased family members, demonstrating the feasibility and importance of this approach. One of the two families with evidence of linkage between breast cancer and genetic markers flanking BRCA1 represents the first such family of African-American descent to be reported in detail.

Isolation and partial characterization of lipoprotein A-II (LP-A-II) particles of human plasma.

High density lipoproteins (HDL) consist of a mixture of chemically and functionally distinct families of particles defined by their characteristic apolipoprotein (Apo) composition. The two major lipoprotein families are lipoprotein A-I (LP-A-I) and lipoprotein A-I:A-II (LP-A-I:A-II). This study describes the isolation of a third minor HDL family of particles referred to as lipoprotein A-II (LP-A-II) because it lacks ApoA-I and contains ApoA-II as its main or sole apolipoprotein constituent. Because ApoA-II is an integral protein constituent of three distinct lipoprotein families (LP-A-I:A-II, LP-A-II: B:C:D:E and LP-A-II), LP-A-II particles were isolated from whole plasma by sequential immunoaffinity chromatography on immunosorbers with antisera to ApoA-II, ApoB and ApoA-I, respectively. In normolipidemic subjects, the concentration of LP-A-II particles, based on ApoA-II content, is 4-18 mg/dl accounting for 5-20% of the total ApoA-II not associated with ApoB-containing lipoproteins. The lipid composition of LP-A-II particles is characterized by low percentage of triglycerides and cholesterol esters and a high percentage of phospholipids in comparison with lipid composition of LP-A-I and LP-A-II: A-II. The major part of LP-A-II particles contain ApoA-II as the sole apolipoprotein constituent; however, small subsets of LP-A-II particles may also contain ApoD and other minor apolipoproteins. The lipid/protein ratio of LP-A-II is higher than those of LP-A-I and LP-A-I:A-II. In homozygous ApoA-I and ApoA-I/ApoC-III deficiencies, LP-A-II particles are the only ApoA-containing high density lipoprotein with levels found to be within the same range (7-13 mg/dl) as those of normolipidemic subjects. However, in contrast to normal LP-A-II, their lipid composition is characterized by higher percentages of triglycerides and cholesterol esters and a lower percentage of phospholipids and their apolipoprotein composition by the presence of ApoC-peptides and ApoE in addition to ApoA-II and ApoD. These results show that LP-A-II particles are a minor HDL family and suggest that, in the absence of ApoA-I-containing lipoproteins, they become an efficient acceptor/donor of ApoC-peptides and ApoE required for a normal metabolism of triglyceride-rich lipoproteins. Their other possible functional roles in lipid transport remain to be established in future experiments.

Genetics of the multiple endocrine neoplasia type 2B syndrome.

Multiple endocrine neoplasia type 2B (MEN 2B) is similar to MEN 2A in that both autosomal dominant syndromes include medullary thyroid cancers and pheochromocytomas. It is distinct in that MEN 2B patients have much earlier age of onset with more aggressive tumors and mucosal neuromas of the lips and tongue. The neuromas allow ascertainment generally before age 5. Studies of two and three generations of 14 MEN 2B families disclosed close linkage of the MEN 2B gene to DNA markers to which MEN2A had been linked. Multipoint analysis utilizing additional results in three generations of a 15th family have disclosed a peak total lod score of 8.89 at the midpoint between the centromere markers D10Z1 and RBP3 on the long arm (band q11). One recombinant was observed between D10Z1 and MEN2B, but this individual was not recombinant with D10S94. These studies suggest physical proximity of MEN2A and MEN2B but do not establish allelism for the gene(s).

Characterization of apoA- and apoB-containing lipoprotein particles in a variant of familial apoA-I deficiency with planar xanthoma: the metabolic significance of LP-A-II particles.

This study describes a variant of familial apoA-I deficiency associated with a moderate risk for premature coronary artery disease. The proband, a 25-year-old man of Philippine origin, and his 62-year-old maternal aunt had peripheral corneal opacification, xanthelasma, and planar xanthoma; the aunt had coronary artery bypass surgery at 61 years of age. Proband's parents and three brothers were asymptomatic and apparently healthy. The characteristic apolipoprotein features of affected patients were the immunochemically and chemically undetectable apoA-I, reduced levels of apoA-II, apoC-II, apoC-III, and apoD, and normal levels of apoB and apoE; except for negligible levels of high density lipoprotein (HDL)-cholesterol (2-3 mg/dl), their plasma lipid profile was normal. The apoA-I levels in all five unaffected relatives were more than one SD below the normal mean values for their age and sex; the HDL-cholesterol levels of proband's unaffected brothers were below the 10th percentile of normal control values. Patient's very low density lipoprotein (VLDL), low density lipoprotein (LDL), and HDL contained 1.4, 80.4, and 18.1%, whereas those of control subjects contained 2.7, 28.8, and 68.1% of the total apolipoprotein mass, respectively. In unaffected relatives, the levels of LP-A-I, but not LP-A-I:A-II, were significantly lower than in controls. Neither of the two patients had detectable concentrations of LP-A-I or LP-A-I:A-II. Their HDL only consisted of LP-A-II particles, the levels of which (7-13 mg/dl) were similar to those of unaffected relatives or controls. There was no difference in the lipid composition of LP-A-II between patients and their relatives. However, LP-A-II from patients contained substantial amounts of apoC-peptides and apoE (0.40-0.98 mg/mg apoA-II), whereas those from unaffected relatives were free of these minor apolipoproteins. In patients, among all four major apoB-containing lipoproteins, only the levels of LP-B and LP-B:C were slightly higher than those in controls. Results of this study suggest a genetic cause for this variant of apoA-I deficiency characterized most probably by autosomal recessive inheritance. It appears that patients are likely to be homozygous for a gene present in single dose in the parents and brothers of the affected proband.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of apolipoprotein activators on the specificity of lecithin:cholesterol acyltransferase: determination of cholesteryl esters formed in A-I/C-III deficiency.

Although it is known that plasma lecithin:cholesterol acyltransferase (LCAT) is activated by several apolipoproteins (apo) including A-I, C-I, D, A-IV, and E, it is not clear what the physiological importance of having different apolipoprotein activators is. One possible explanation is that the activation by different apolipoproteins may result in the utilization of different species of phosphatidylcholine (PC), leading to the formation of different species of cholesteryl esters (CE). In order to determine this possibility, we analyzed the molecular species composition of PC and CE in two patients with familial deficiency of apoA-I and apoC-III. The LCAT activity, assayed by three different procedures, was found to be 36-63% of the control value. The lower LCAT activity, however, was due to deficiency of the enzyme rather than the absence of apoA-I. The patients' plasma was relatively enriched with sn-2 18:2 PC species reflecting the partial deficiency of LCAT activity. The fatty acid composition of plasma CE was not significantly different from that of controls. HPLC analysis of labeled CE formed after incubation of plasma with [C14]cholesterol showed no significant difference in the species of CE synthesized by the LCAT reaction. The transfer of pre-existing as well as newly formed CE from HDL to the apoB-containing lipoproteins was accelerated compared to control plasma. These results show that the absence of apoA-I does not significantly affect either the activity or the specificity of LCAT, and that the other apolipoprotein activators can substitute adequately for it.

Hereditary hyperparathyroidism and multiple ossifying jaw fibromas: a clinically and genetically distinct syndrome.

A large previously reported family with hyperparathyroidism has been reinvestigated recently because of the occurrence of multiple ossifying jaw fibromas in two affected members of the third generation similar to the jaw tumors of four of five affected members of the first generation. These maxillary and mandibular tumors can be differentiated from the "brown tumors" of hyperparathyroidism because they can appear and enlarge even though the hypercalcemia is surgically corrected. These tumors are histologically distinct fibroosseous lesions without the giant cells seen in "brown tumors." The parathyroid enlargement was mostly uniglandular, with multiple tumors found occasionally. Studies in DNA linkage were performed within this large family and a similar family in Houston to determine if the gene for this syndrome, termed HRPT2, is linked to DNA markers on chromosome 11, to which the gene for multiple endocrine neoplasia (MEN) type 1 has been linked. (This linkage is supported by our findings in one family with MEN 1 reported here.) Linkage studies were also performed with markers on chromosome 10, to which the genes for MEN 2A and MEN 2B have been linked. Evidence against close linkage with chromosome 10 and chromosome 11 markers suggests that this clinically distinct syndrome is also genetically distinct.

Linkage of the multiple endocrine neoplasia type 2B gene (MEN2B) to chromosome 10 markers linked to MEN2A.

The syndrome of multiple endocrine neoplasia type 2B (MEN 2B) resembles that of MEN 2A in that both include medullary carcinoma of the thyroid, pheochromocytoma, and autosomal dominant inheritance, but is distinct in that MEN 2B patients have neuromas of the mucous membranes. MEN2A has been linked to RBP3, D10S5, FNRB, D10S15, and D10Z1 near the centromere of chromosome 10. We examined linkage between MEN2B and RFLPs on chromosome 10 in all available members in two or three generations of 14 kindreds. The centromere marker D10Z1 was linked to MEN2B with a peak lod score of 5.42 at theta = 0.02. One possible recombinant was observed between D10Z1 and MEN2B. Multipoint analysis of RFLPs at FNRB, D10Z1, RBP3, and D10S15 gave a peak lod score of 7.12 at the midpoint between D10Z1 and RBP3 on the long arm (band q11). The most likely gene order FNRB-D10Z1-MEN2B was 27 times more likely than MEN2B-FNRB-D10Z1 and 31/2 times more likely than FNRB-MEN2B-D10Z1. Additional data will be required to establish the order of these loci with confidence.

Genetic mechanisms of neoplasia in MEN 2.

Several possible mechanisms for the initiation and progression of tumors in multiple endocrine neoplasia type 2 (MEN 2) merit consideration. Localization of MEN2A to the pericentromeric area of chromosome 10 indicates the site of the initial mutagenic event but does not explain the tissue specificity observed. The consistency of tissue involvement within families, despite the variability between families, suggests that the tumors result from separate but contiguous tissue-specific genes arranged in a particular linear order. Linkage studies in MEN 2A and 2B families are compatible with this contiguous gene theory. Data suggest that Knudson's two-mutational-event theory is applicable in MEN 2, with cellular hyperplasia resulting from the initial heritable mutation. The second event could be a homozygous allelic mutation, but the lack of consistent loss of heterozygosity of chromosome 10 markers in tumors suggests other mechanisms. Observations in MEN 2 may be explained by the heritable chromosome 10 mutation causing hyperplasia, with the hyperplastic cells being converted to cancer cells by second mutations at any of many possible sites. Tumor progression probably involves subsequent events at other loci. These hypotheses may have important clinical implications.

MEN-2 tumor associations suggest a linear order of specific endocrine tumor genes.

The variation in tumor involvement between families and consistent pattern within 12 MEN-2A and 4 MEN-2B families studied suggest that the tumors in MEN-2 result from separate, specific mutations in a specific linear order of adjacent genes.

Pathologic findings in adrenoleukodystrophy heterozygotes.

Two women, heterozygous for X-linked adrenoleukodystrophy, contained striated adrenocortical cells without inflammation and central nervous system demyelinative lesions. Only one was symptomatic neurologically; neither exhibited hypoadrenalism. These findings further document the variability of adrenoleukodystrophy heterozygotes and provide evidence that the major pathologic differences between hemizygote and heterozygote are quantitative in nature.

Identical twins with hereditary hemorrhagic telangiectasia concordant for cerebrovascular arteriovenous malformations.

Central nervous system arteriovenous malformations are uncommon in hereditary hemorrhagic telangiectasia. Identical twins are described with hereditary hemorrhagic telangiectasia and concordance for central nervous system arteriovenous malformations identified by angiography. One twin had a central nervous system hemorrhage in the seventh month of pregnancy and also had a pulmonary arteriovenous malformation. The other was asymptomatic. A previously reported association between HLA type A2 BW17 and hereditary hemorrhagic telangiectasia was not confirmed. Two recombinations were identified between the loci for HLA and hereditary hemorrhagic telangiectasia. The loci for HLA and hereditary hemorrhagic telangiectasia are not closely linked. Stroke in a young person should prompt an inspection for manifestations of hereditary hemorrhagic telangiectasia.

Identification of human red cell glutamate-pyruvate transaminase (GPT) phenotypes by isoelectric focusing.

Isoenzymes of human red cell glutamate-pyruvate transaminase (GPT) were resolved by isoelectric focusing (IEF) of hemolysates in polyacrylamide gels at pH 5.0-7.0. The bands of enzyme activity required both alpha-ketoglutarate and L-alanine in the staining mixture for visualization, indicating that the bands were not lactate dehydrogenase or glutamate dehydrogenase. Phenotyping of 41 individuals by IEF, including types GPT 1, 2A, 1-2A, 1-2B, and 2A-2B, agreed with the typing results obtained by electrophoresis in starch gels and in polyacrylamide gels at acid and alkaline pH. Analysis of one kindred demonstrated autosomal codominant transmission of the rare GPT*2B gene through 3 generations. IEF facilitates phenotyping by permitting identification of the GPT types on a single gel with a considerable reduction in time and cost. Although no new variants were found in this investigation, IEF may be more powerful for the recognition of presently undetected variants of GPT.

Clinical value of tumor doubling estimations in multiple endocrine neoplasia type II.

Experience with children with multiple endocrine neoplasia (MEN) type IIb has emphasized that medullary thyroid cancer (MTC) in MEN IIb is more aggressive than in MEN IIa. Earlier ages of onset and apparently more rapid growth of MTC in MEN IIb suggest that these tumors have earlier ages of conversion to malignant states and/or shorter doubling times. The age at which a hyperplastic C cell becomes a malignant cell and the true doubling time cannot be estimated presently. Maximum volume-doubling times of 35 and 75 days (21 to 26 doublings) were calculated from tumor size and age at operation in five patients with MEN IIb aged 2 to 5 years. Calculations in 20 patients with MEN IIa revealed maximum doubling times of 110 to 440 days, with ages ranging from 7 to 29 years and number of doubling ranging from 18 to 38. Positive provocative calcitonin tests in two adult patients with MEN IIa after 10 to 11 years of repeated negative tests suggest a minimum doubling time of 190 to 210 days. Such experience emphasizes that negative stimulated calcitonin tests less than 11 years after operation do not provide assurance of cures for MTC in MEN IIa although negative tests after more than 5 years for MEN IIb are encouraging. Calculations of volume doublings accounting for various-sized tumors are compatible with Knudson's two-mutational-event theory on the initiation of neoplasia.

Familial apolipoprotein AI and apolipoprotein CIII deficiency. Subclass distribution, composition, and morphology of lipoproteins in a disorder associated with premature atherosclerosis.

Lipoprotein classes isolated from the plasma of two patients with apolipoprotein AI (apo AI) and apolipoprotein CIII (apo CIII) deficiency were characterized and compared with those of healthy, age- and sex-matched controls. The plasma triglyceride values for patients 1 and 2 were 31 and 51 mg/dl, respectively, and their cholesterol values were 130 and 122 mg/dl, respectively; the patients, however, had no measurable high density lipoprotein (HDL)-cholesterol. Analytic ultracentrifugation showed that patients' S degrees f 0-20 lipoproteins possess a single peak with S degrees f rates of 7.4 and 7.6 for patients 1 and 2, respectively, which is similar to that of the controls. The concentration of low density lipoprotein (LDL) (S degrees f 0-12) particles, although within normal range (331 and 343 mg/dl for patients 1 and 2, respectively), was 35% greater than that of controls. Intermediate density lipoproteins (IDL) and very low density lipoproteins (VLDL) (S degrees f 20-400) were extremely low in the patients. HDL in the patients had a calculated mass of 15.4 and 11.8 mg/dl for patients 1 and 2, respectively. No HDL could be detected by analytic ultracentrifugation, but polyacrylamide gradient gel electrophoresis (gge) revealed that patients possessed two major HDL subclasses: (HDL2b)gge at 11.0 nm and (HDL3b)gge at 7.8 nm. The major peak in the controls, (HDL3a)gge, was lacking in the patients. Gradient gel analysis of LDL indicated that patients' LDL possessed two peaks: a major one at 27 nm and a minor one at 26 nm. The electron microscopic structure of patients' lipoprotein fractions was indistinguishable from controls. Patients' HDL were spherical and contained a cholesteryl ester core, which suggests that lecithin/cholesterol acyltransferase was functional in the absence of apo AI. The effects of postprandial lipemia (100-g fat meal) were studied in patient 1. The major changes were the appearance of a 33-nm particle in the LDL density region of 1.036-1.041 g/ml and the presence of discoidal particles (12% of total particles) in the HDL region. The latter suggests that transformation of discs to spheres may be delayed in the patient. The simultaneous deficiency of apo AI and apo CIII suggests a dual defect in lipoprotein metabolism: one in triglyceride-rich lipoproteins and the other in HDL. The absence of apo CIII may result in accelerated catabolism of triglyceride-rich particles and an increased rate of LDL formation. Additionally, absence of apo CIII would favor rapid uptake of apo E-containing remnants by liver and peripheral cells. Excess cellular cholesterol would not be removed by the reverse cholesterol transport mechanism since HDL levels are exceedingly low and thus premature atherosclerosis occurs.

Effect of blood high density lipoprotein cholesterol concentration on fecal steroid excretion in humans.

Daily excretion of fecal total bile acids and neutral steroids were compared in five controls and two patients with extremely low concentrations of plasma high density lipoprotein (3 to 11 mg/dl) and severe atherosclerosis. There was no significant difference in steroid excretion rates in the groups. The predominant bile acid excreted in control feces was deoxycholic acid; lithocholic acid was predominant in the patients. The patients showed no signs of significant liver disease.