Gonadal function in patients with beta thalassaemia major.

Endocrine studies were made on 23 female patients aged 13 to 29 years, with delayed puberty or primary amenorrhoea and beta thalassaemia major, and 12 healthy controls, of whom six were prepubertal and six were in Tanner's stage 3-4. Each patient and control received a single intravenous dose of 100 micrograms gonadotrophin releasing hormone (GnRH), and one week later, 10 U/kg body weight of human menopausal gonadotrophin (hMG) to stimulate ovarian function. The patients had decreased gonadotrophin reserves when compared with those of normal controls, only one of 23 patients had an intact luteinising hormone and follicle stimulating hormone response. Most of the thalassaemic patients with delayed puberty showed normal gonad response to human menopausal gonadotrophin (hMG), but three had very low responses, when compared with that of controls. The gonadal failure was even more severe in four of six patients with primary amenorrhoea. It is important to assess hypothalamic-pituitary-gonadal function in young women with beta thalassaemia major, so that those with glandular dysfunction may be started on replacement therapy.     

Gonadal function in men with the Martin-Bell (fragile-X) syndrome

We evaluated testicular function in 15 men with the Martin-Bell (fragile-X) mental retardation syndrome. Macro-orchidism was present in all subjects. Their mean serum LH and FSH levels and plasma testosterone and dihydrotestosterone levels were normal. The mean plasma levels of androstenedione, 17-hydroxyprogesterone, and progesterone were slightly elevated above the normal range, whereas the plasma levels of dehydroepiandrosterone and dehydroepiandrosterone-sulfate were normal. The response in the levels of plasma testosterone following a 5 day period of hCG stimulation was normal in 8 subjects and there was no abnormal accumulation of androgen precursors. The level of 5 alpha-reductase activity and androgen receptor binding was normal in genital skin fibroblasts derived from 3 of these patients. The response of gonadotropin secretion to GnRH stimulation was normal in the 8 men who were tested. Therefore, our data are consistent with the hypothesis that testicular enlargement in men with the Martin-Bell syndrome is not mediated by hormonal factors.     

Acquired glomerular lesions in patients with Down syndrome

The long-term survival of persons with Down syndrome has dramatically increased over the past 50 years. There are no studies addressing the spectrum of glomerular lesions in these patients. We reviewed the clinical-pathologic characteristics of 17 patients with Down syndrome who underwent renal biopsy. The cohort consisted of 12 whites and 5 African Americans with mean age of 29 years (range, 6-45 years). History of hypothyroidism was present in 8 patients. Renal presentations included renal insufficiency (15 patients, mean serum creatinine 3.4 mg/dL), proteinuria (all patients, including 3 with nephrotic syndrome, mean 24-hour urine protein 4.2 g), and hematuria (14 patients, including 4 with gross hematuria). The glomerular diseases found on biopsy were IgA nephropathy (n = 5 patients), focal segmental glomerulosclerosis (n = 4), membranoproliferative glomerulonephritis (n = 2), acute postinfectious glomerulonephritis (n = 2), pauci-immune crescentic glomerulonephritis (n = 2), membranous glomerulonephritis (n = 1), and lupus nephritis (n = 1). Follow-up (mean, 47 months; range, 2-141 months) was available on 16 patients (94%). Two patients (1 with membranous glomerulonephritis and 1 with acute postinfectious glomerulonephritis) had complete remission; 8 patients (4 with IgA nephropathy, 2 with focal segmental glomerulosclerosis, 1 with lupus nephritis, and 1 with acute postinfectious glomerulonephritis) had chronic kidney disease; and 6 patients (2 with pauci-immune crescentic glomerulonephritis, 2 with membranoproliferative glomerulonephritis, 1 with IgA nephropathy, and 1 with focal segmental glomerulosclerosis) progressed to end-stage renal disease, 4 of whom died. In summary, a wide spectrum of glomerular diseases can be seen in patients with Down syndrome, with IgA nephropathy and focal segmental glomerulosclerosis being the most common. Renal biopsy is necessary to determine the type of glomerular lesion and appropriate treatment.     

Neutrophil oxidative metabolism in Down syndrome patients with congenital heart defects

Down syndrome (DS) occurs when an individual has three, rather than two, copies of the 21st chromosome. Cytosolic superoxide dismutase (SOD‐1) is encoded by a gene on chromosome 21 and thus, SOD‐1 activity is elevated in patients with DS. Forty percent of all cases with DS are associated with congenital heart defects (CHD). Although the contribution of SOD1 to disease phenotype is unknown, it is considered to be a “molecular marker” of the disease. It was hypothesized herein that the presence of CHD may alter the expression of SOD1 and oxidative metabolism in patients with DS. This hypothesis was tested via four experimental groups as follows: patients with DS without CHD, DS patients with CHD, CHD patients without DS and controls. Expression and activity of superoxide dismutase (SOD), glutathione peroxidase (GPx), myeloperoxidase (MPO), and catalase (CAT) were determined in neutrophils from all experimental groups. Intracellular hydrogen peroxide concentration and superoxide release were also evaluated in neutrophils. A significant increase was observed in SOD and GPx amount and activity in patients with DS with and without CHD. No significant difference was found in the amount and activity of MPO and CAT among the different experimental groups. Intracellular hydrogen peroxide concentration was similar in all groups, whereas a prominent decrease was seen in superoxide release in cases with DS. Patients with DS with and without CHD showed no significant differences in any of the measured parameters. The data suggest that CHD observed in patients with DS does not result from altered redox metabolism associated with the disease. Environ. Mol. Mutagen., 2010. © 2009 Wiley‐Liss, Inc.     

The mortality of adults with Down syndrome as a function of age

This study sought to test the hypothesis that adults with Down Syndrome may age faster than the general population by comparing the rate of increase in their mortality with age with that of the general population by the method originally described by Gompertz. The differences were not statistically significant. There is a striking difference in morbidity, the Down's adults being highly vulnerable. Alzheimer populations do not lend themselves readily to this type of analysis.     

Gonadal mosaicism in severe Pallister-Hall syndrome

Pallister-Hall syndrome (PHS, MIM #146510) is characterized by central and postaxial polydactyly, hypothalamic hamartoma (HH), bifid epiglottis, imperforate anus, renal abnormalities, and pulmonary segmentation anomalies. It is inherited in an autosomal dominant pattern. Here, we describe a family with two affected children manifesting severe PHS with mental retardation, behavioral problems, and intractable seizures. Both parents are healthy, with normal intelligence, and have no malformations on physical, laryngoscopic, and cranial MRI exam. The atypical presentation of these children and the absence of parental manifestations suggested an autosomal recessive mode of inheritance or gonadal mosaicism. Sequencing of GLI3 revealed a two nucleotide deletion in exon 15 (c.3385_3386delTT) predicting a frameshift and premature stop at codon 1129 (p.F1129X) in the children while both parents have wild type alleles. Genotyping with GLI3 intragenic markers revealed that both children inherited the abnormal allele from their mother thus supporting gonadal mosaicism as the underlying mechanism of inheritance (paternity was confirmed). This is the first reported case of gonadal mosaicism in PHS. The severe CNS manifestations of these children are reminiscent of children with non-syndromic HH who often have progressive mental retardation with behavioral problems and intractable seizures. We conclude that the phenotypic spectrum of PHS can include severe CNS manifestations and that recurrence risks for PHS should include a proviso for gonadal mosaicism, though the frequency cannot be calculated from a single case report. Published 2003 Wiley-Liss, Inc.     

Clinical manifestations of hematologic and oncologic disorders in patients with Down syndrome

Hematologic abnormalities are common in individuals with Down syndrome (DS). Increased erythrocyte mean corpuscular volume (MCV) is frequently found among DS infants and remains elevated throughout life in two-thirds of patients, making interpretation of red cell indices for diagnosis of nutritional anemias or bone marrow failure disorders more challenging. Transient myeloproliferative disorder (TMD) associated with pancytopenia, hepatosplenomegaly, and circulating immature WBCs, is found almost exclusively in DS infants with an incidence of approximately 10%. In most cases, TMD regresses spontaneously within the first 3 months of life, but in some children, it can be life threatening or even fatal. Despite the high rate of spontaneous regression, TMD can be a preleukemic disorder in 20-30% of children with DS. The types of malignancy, response to therapy, and clinical outcome in children with DS are also unique. There is an increased risk of leukemia with an equal incidence of lymphoid and myeloid leukemia. Acute megakaryocytic leukemia (AMKL) subtype is the most common form of acute myeloid leukemia (AML) in this setting, and is uncommon in children without DS. Somatic mutations of the gene encoding the hematopoetic growth factor GATA1 have been shown to be specific for TMD and AMKL in children with DS. Myelodysplastic syndrome can precede AML. Children with DS and leukemia are more sensitive to some chemotherapeutic agents such as methotrexate than other children which requires careful monitoring for toxicity. Although the risk for leukemia is higher in individuals with DS, these patients have a lower risk of developing solid tumors, with the exception of germ cell tumors, and perhaps retinoblastoma and lymphoma.     

Olfactory impairment increases as a function of age in persons with Down syndrome.

Neuropathology similar to that found in the brains of patients with Alzheimer's disease (AD) has consistently been observed in older individuals with Down syndrome (DS) and this neuropathology is particularly prevalent in areas involved in olfaction. The present study investigated the effects of age on the expression of olfactory impairment in Down syndrome to address the hypothesis that older adults with DS show greater deficits in olfactory function compared with younger persons with DS and compared with age and IQ matched control groups. Between group differences showed that persons with DS had significant deficits in olfactory functioning compared to the two control groups. Further, within the DS group, older adults performed more poorly than the young adults or children. Results support the hypothesis that in a group of persons at risk for AD because of DS, olfactory impairment is greater in older individuals, suggesting progressive impairment over time. Deficits in olfactory function may be useful in signalling incipient dementia in DS.     

Caries in Portuguese children with Down syndrome

OBJECTIVES:

Oral health in Down syndrome children has some peculiar aspects that must be considered in the follow-up of these patients. This study focuses on characterizing the environmental and host factors associated with dental caries in Portuguese children with and without Down syndrome.

METHODS:

A sibling-matched, population-based, cross-sectional survey was performed.

RESULTS:

Down syndrome children presented a significantly greater percentage of children without caries, 78% vs. 58% of non-Down syndrome siblings. This difference in the DMFT index (number of decayed, missing and filled teeth) essentially reflects data obtained from treated teeth, for which 91% of children with Down syndrome had never had a tooth treated vs. 67% of siblings. This result was statistically significant, whereas results for decayed and lost teeth did not differ between Down syndrome children and their unaffected siblings. Additionally, in Down syndrome children, a delayed eruption of the second molar occurs. Down syndrome children and their siblings have similar oral hygiene habits, but a higher percentage of Down syndrome children visit a dentist before the age of three years, in comparison to their siblings. Bruxism was also more common in Down syndrome children compared to their siblings.

CONCLUSIONS:

Our results show that Portuguese children with Down syndrome have lower caries rates than children without Down syndrome. This reduced prevalence may be associated with the parents'' greater concern about oral health care in Down syndrome children, resulting in their taking them sooner to visit a dentist, as well as to a higher bruxism prevalence and delayed tooth eruption.     

Acute leukemias in children with Down syndrome

Children with Down syndrome (DS) often present with hematopoietic abnormalities, and are at increased risk of developing leukemia. Specifically, 3-10% of newborns with DS are diagnosed with transient myeloproliferative disease, and children with DS are 500 times more likely to develop acute megakaryoblastic leukemia (AMKL) and 20 times more likely to develop acute lymphoblastic leukemia (ALL) than typical children. This review examines the characteristics of these leukemias and their development in the unique genetic background of trisomy 21. A discussion is also provided for areas of future research and potential therapeutic development.