23 research outputs found
Neonatal McCune-Albright syndrome: a unique syndromic profile with an unfavorable outcome
Somatic gain-of-function mutations of GNAS cause a spectrum of clinical phenotypes, ranging from McCune-Albright syndrome (MAS) to isolated disease of bone, endocrine glands, and more rarely, other organs. In MAS, a syndrome classically characterized by polyostotic fibrous dysplasia (FD), cafe-́ au-lait (CAL) skin spots, and precocious puberty, the heterogenity of organ involvement, age of onset, and clinical severity of the disease are thought to reflect the variable size and the random distribution of the mutated cell clone arising from the postzygotic mutation. We report a case of neonatal MAS with hypercortisolism and cholestatic hepatobiliary dysfunction in which bone changes indirectly emanating from the disease genotype, and distinct from FD, led to a fatal outcome. Pulmonary embolism of marrow and bone fragments secondary to rib fractures was the immediate cause of death. Ribs, and all other skeletal segments, were free of changes of typical FD and fractures appeared to be the result of a mild-to-moderate degree of osteopenia. The mutated allele was abundant in the adrenal glands and liver, but not in skin, muscle, and fractured ribs, where it could only be demonstrated using a much more sensitive PNA hybridization probe-based FRET (F€orster resonance energy transfer) technique. Histologically, bilateral adrenal hyperplasia and cholestatic disease matched the abundant disease genotype in the adrenals and liver. Based on this case and other sporadic reports, it appears that gain-of-function mutations of GNAS underlie a unique syndromic profile in neonates characterized by CAL skin spots, hypercortisolism, hyperthyroidism, hepatic and cardiac dysfunction, and an absence (or latency) of FD, often with a lethal outcome. Taken together, our and previous cases highlight the phenotypic severity and the diagnostic and therapeutic challenges of MAS in neonates. Furthermore, our case specifically points out how secondary bone changes, unrelated to the direct impact of the mutation, may contribute to the unfavorable outcome of very early-onset MAS
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Ethnic differences in progression of islet autoimmunity and type 1 diabetes in relatives at risk
We hypothesised that progression of islet autoimmunity and type 1 diabetes mellitus differs among races/ethnicities in at-risk individuals.
In this study, we analysed the data from the Type 1 Diabetes TrialNet Pathway to Prevention Study. We studied 4873 non-diabetic, autoantibody-positive relatives of individuals with type 1 diabetes followed prospectively (11% Hispanic, 80.9% non-Hispanic white [NHW], 2.9% non-Hispanic black [NHB] and 5.2% non-Hispanic other [NHO]). Primary outcomes were time from single autoantibody positivity confirmation to multiple autoantibody positivity, and time from multiple autoantibody positivity to type 1 diabetes mellitus diagnosis.
Conversion from single to multiple autoantibody positivity was less common in Hispanic individuals than in NHW individuals (HR 0.66 [95% CI 0.46, 0.96], p = 0.028) adjusting for autoantibody type, age, sex, Diabetes Prevention Trial Type 1 Risk Score and HLA-DR3-DQ2/DR4-DQ8 genotype. In participants who screened positive for multiple autoantibodies (n = 2834), time to type 1 diabetes did not differ by race/ethnicity overall (p = 0.91). In children who were <12 years old when multiple autoantibody positivity was determined, being overweight/obese had differential effects by ethnicity: type 1 diabetes risk was increased by 36% in NHW children (HR 1.36 [95% CI 1.04, 1.77], p = 0.024) and was nearly quadrupled in Hispanic children (HR 3.8 [95% CI 1.6, 9.1], p = 0.0026). We did not observe this interaction in participants who were ≥12 years old at determination of autoantibody positivity, although this group size was limited. No significant differential risks were observed between individuals of NHB and NHW ethnicity.
The risk and rate of progression of islet autoimmunity were lower in Hispanic compared with NHW at-risk individuals, while significant differences in the development of type 1 diabetes were limited to children <12 years old and were modified by BMI
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The Effect of Ethnicity in the Rate of Beta-Cell Functional Loss in the First 3 Years After Type 1 Diabetes Diagnosis
We set forth to compare ethnicities for metabolic and immunological characteristics at the clinical diagnosis of type 1 diabetes (T1D) and assess the effect of ethnicity on beta-cell functional loss within 3 years after clinical diagnosis.
We studied participants in TrialNet New Onset Intervention Trials (n = 624, median age = 14.4 years, 58% male, 8.7% Hispanic) and followed them prospectively for 3 years. Mixed meal tolerance tests (MMTT) were performed within 6 months following clinical diagnosis and repeated semiannually. Unless otherwise indicated, analyses were adjusted for age, sex, BMI Z-score, and diabetes duration.
At T1D clinical diagnosis, Hispanics, compared with non-Hispanic whites (NHW), had a higher frequency of diabetic ketoacidosis (DKA) (44.7% vs 25.3%, OR = 2.36, P = 0.01), lower fasting glucose (97 vs 109 mg/dL, P = 0.02) and higher fasting C-peptide (1.23 vs 0.94 ng/mL, P = 0.02) on the first MMTT, and higher frequency of ZnT8 autoantibody positivity (n = 201, 94.1% vs 64%, OR = 7.98, P = 0.05). After exclusion of participants in experimental arms of positive clinical trials, C-peptide area under the curve (AUC) trajectories during the first 3 years after clinical diagnosis were not significantly different between Hispanics and NHW after adjusting for age, sex, BMI-z score, and DKA (n = 413, P = 0.14).
Despite differences in the metabolic and immunological characteristics at clinical diagnosis of T1D between Hispanics and NHW, C-peptide trajectories did not differ significantly in the first 3 years following clinical diagnosis after adjustment for body mass index and other confounders. These findings may inform the design of observational studies and intervention trials in T1D
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