Monica Vincenzi

Lack of expression of SERPINF1, the gene coding for pigment epithelium-derived factor, causes progressively deforming osteogenesis imperfecta with normal type I collagen

Osteogenesis imperfecta (OI) is a clinically heterogeneous heritable connective tissue disorder, characterized by low bone mass and reduced strength, which result in susceptibility to fracture and bone deformities. In most cases it is caused by dominant mutations in type I collagen genes, COL1A1 and COL1A2. Recessive forms, which collectively account for approximately 5% of cases of osteogenesis imperfecta detected in North America and Europe, are caused instead by mutations in various genes coding for proteins involved in collagen posttranslational modifications, folding, and secretion. A novel disease locus, SERPINF1, coding for pigment epithelium‐derived factor (PEDF), has been found recently. In SERPINF1 mutants described so far, synthesis, posttranslational modification, and secretion of type I collagen were reported to be normal. Here we describe three siblings born to consanguineous parents, who show an initially mild and then progressively worsening form of OI with severe deformities of the long bones. They are homozygous for a frameshift mutation in exon 4 of the SERPINF1 gene, which leads to lack of the transcription/translation product, likely a key factor in bone deposition and remodeling. Synthesis and secretion of type I collagen are normal. Clinical, radiographic, histological, and histomorphometric data from the proband are reminiscent of the distinctive features of type VI OI.

Congenital hypothyroidism with delayed TSH elevation in low-birth-weight infants: incidence, diagnosis and management

OBJECTIVE To evaluate the incidence of congenital hypothyroidism (CH) with delayed TSH elevation among low-birth-weight (LBW) newborns in North-Eastern Italy and to verify if they need a second or third screening. DESIGN Analysis of clinical and biochemical data of newborns affected by CH with delayed TSH elevation identified by neonatal screening. METHODS Data of all newborns with birth weight (BW) <2500 g and evidence of delayed TSH elevation at newborn screening were collected between 2011 and 2014. Confirmatory tests were based on serum TSH and FT4 levels. All their clinical signs at diagnosis were reported. RESULTS 57.5% of LBW newborns with delayed TSH increase at neonatal screening presented a CH with delayed TSH elevation and began a treatment with l-thyroxine. The incidence of this condition in North-Eastern Italy is therefore 1:908. The remaining infants presented a subclinical hypothyroidism (21.25%) or a complete normal serum thyroid function (21.25%). These data could be drawn only from a retesting strategy of neonatal screening. CONCLUSIONS Our report describes the incidence of CH with delayed TSH rise in North-Eastern Italy and differentiates this clinical condition from other thyroid dysfunctions of preterm or LBW newborns. The second-screening strategy for CH in neonates with BW < 2500 g proved useful in detecting newborns who otherwise would not be identified at the first screening.

Implementation of a Congenital Hypothyroidism Newborn Screening Procedure with Mutation Detection on Genomic DNA Extracted from Blood Spots: The Experience of the Italian Northeastern Reference Center

After a couple of decades from the institution of nationwide congenital hypothyroidism (CH) newborn screening program, the first generation properly treated is now displaying normal reproductive rate and the causative molecular defects are spreading from one generation to the next. In the present study we propose a method of detection of mutations in the thyrotropin receptor (TSHR) and in the paired box 8 (PAX8) genes that have been proved to be responsible for some forms of CH. The method, carried out by means of denaturing high-performance liquid chromatography (DHPLC) followed by direct sequencing, takes advantage of the CH newborn screening procedure, because genomic DNA for the analysis is extracted from the same blood spot collected for recall confirmation. Among 16 hypothyroid newborns with thyroid hypoplasia born between January 1999 and April 2005 in northeastern Italy, three heterozygous causative mutations in the TSHR gene were evidenced, whereas the analysis of the PAX8 gene revealed an unknown heterozygous substitution that could interfere with the start of transcription.

Idiopathic Juvenile Osteoporosis: Clinical Experience from a Single Centre and Screening of LRP5 and LRP6 Genes

We report clinical findings, bone mineral density (BMD) and bone biopsy data in ten children with features of classic idiopathic juvenile osteoporosis (IJO). We also screened the patients for mutations in LRP5 and LRP6. We found low BMD in the lumbar spine, the hip and distal radius. In the spine and distal radius, the reduction in BMD was more marked in the trabecular compartment. Biopsy confirmed that the trabecular compartment is more severely involved with reduction in bone formation and increase in bone resorption. No mutations in LRP5 and LRP6 could be identified. IJO is likely to be a heterogeneous bone disorder, and next-generation genomic sequencing studies may help reveal causative genes.

3-hydroxyacyl-coenzyme a dehydrogenase deficiency: identification of a new mutation causing hyperinsulinemic hypoketotic hypoglycemia, altered organic acids and acylcarnitines concentrations.

The human HADH gene encodes the short-chain-L-3-hydroxyacyl-CoA dehydrogenase, the enzyme which catalyzes the third step of the β-oxidation of the fatty acids in the mitochondrial matrix. Loss-of-function mutations in the HADH gene lead to short-chain-L-3-hydroxyacyl-CoA dehydrogenase deficiency, an autosomal recessive genetic defect of unknown prevalence with a wide spectrum of phenotypic variability. As in other metabolic diseases, the diagnostic relevance of the biochemical evaluations, plasma acylcarnitines, and urinary organic acids, are crucially dependent on the clinical conditions of the patient during specimen collection.This paper describes the eighth patient carrying a HADH gene mutation, a new homozygous deletion c.565delG leading to an early stop codon (p.V116Wfs124X), in an infant with hyperinsulininemic hypoglycemia, displaying abnormal patterns of plasma acylcarnitines and urinary organic acids. We conclude that, when the residual catalytic activity of the mutated enzyme is seriously reduced, the biochemical hallmarks of the disease, namely plasma 3-hydroxybutyrylcarnitine and urinary 3-hydroxyglutaric acid, are invariably present.

Serum inhibin B levels before and after varicocelectomy in early adolescence

Background: Whereas no clear relationship has been observed between varicocelectomy and serum inhibin B levels in men, in adolescents comparison between inhibin B levels before and after varicocelectomy is lacking. Aim: To evaluate the effect of varicocele surgical treatment on inhibin B levels in adolescents at the beginning of puberty compared to a group of healthy adolescents. Subjects and methods: We studied 28 adolescents in Tanner 2 pubertal stage with a grade III left-sided varicocele (patients) compared to 13 age- and pubertal stage-matched healthy adolescents (controls). All patients underwent blood tests to determine serum inhibin B levels before and 6 months after varicocelectomy by Palomo procedure. For comparison we investigated inhibin B levels in controls and repeated this test 6 months later. Testicular ultrasound was performed for patients only. Results: Baseline inhibin B concentrations of patients and controls were 109.90±40.26 and 109.33±38.34 pg/ml, respectively. No significant changes were observed in patients’ inhibin B concentrations after varicocelectomy (116.00±42.65 pg/ml), or in controls during the 6 months’ follow-up (99.12±30.09 pg/ml). Doppler examination after treatment shows a complete resolution of varicocele in all the patients without alterations in testicular parenchyma. Conclusions: Varicocelectomy performed on adolescents at T2 pubertal stage might be useful to avoid alteration in inhibin B production and consequently in testicular function. Further studies are necessary to confirm the prognostic value of inhibin B levels and the benefit of early varicocelectomy in preserving the fertility of these adolescents.

Identification of a novel pax8 gene sequence variant in four members of the same family: from congenital hypothyroidism with thyroid hypoplasia to mild subclinical hypothyroidism.

BackgroundCongenital hypothyroidism is often secondary to thyroid dysgenesis, including thyroid agenesis, hypoplasia, ectopic thyroid tissue or cysts. Loss of function mutations in TSHR, PAX8, NKX2.1, NKX2.5 and FOXE1 genes are responsible for some forms of inherited congenital hypothyroidism, with or without hypoplastic thyroid. The aim of this study was to analyse the PAX8 gene sequence in several members of the same family in order to understand whether the variable phenotypic expression, ranging from congenital hypothyroidism with thyroid hypoplasia to mild subclinical hypothyroidism, could be associated to the genetic variant in the PAX8 gene, detected in the proband.MethodsWe screened a hypothyroid child with thyroid hypoplasia for mutations in PAX8, TSHR, NKX2.1, NKX2.5 and FOXE1 genes. We studied the inheritance of the new variant R133W detected in the PAX8 gene in the proband’s family, and we looked for the same substitution in 115 Caucasian European subjects and in 26 hypothyroid children. Functional studies were performed to assess the in vitro effect of the newly identified PAX8 gene variant.ResultsA new heterozygous nucleotide substitution was detected in the PAX8 DNA-binding motif (c.397C/T, R133W) in the proband, affected by congenital hypothyroidism with thyroid hypoplasia, in his older sister, displaying a subclinical hypothyroidism associated with thyroid hypoplasia and thyroid nodules, in his father, affected by hypothyroidism with thyroid hypoplasia and thyroid nodules, and his first cousin as well, who revealed only a subclinical hypothyroidism. Functional studies of R133W-PAX8 in the HEK293 cells showed activation of the TG promoter comparable to the wild-type PAX8.ConclusionsIn vitro data do not prove that R133W-PAX8 is directly involved in the development of the thyroid phenotypes reported for family members carrying the substitution. However, it is reasonable to conceive that, in the cases of transcriptions factors, such as Pax8, which establish several interactions in different protein complexes, genetic variants could have an impact in vivo.

Genotype in the diagnosis of 21-hydroxylase deficiency: Who should undergo CYP21A2 analysis?

Aims: to confirm the diagnosis of 21-hydroxylase deficiency (21-OHD) by the analysis of CYP21A2 gene in infants with clinical and/or biochemical features of 21-OHD in order to clarify which patients to submit to genetic analysis; to analyze the genotype-phenotype concordance in these infants. Subjects and methods: We studied 25 children with clinical and/or biochemical features of 21-OHD. All of them and their parents were submitted to genetic analysis of CYP21A2. Patients were classified in 3 groups according to mutations’ severity: severe (group A), moderate (group B) or mild (group C). Results: CYP21A2 gene mutations were found in 17 children. Whereas all infants of groups A and B presented a classical form of 21-OHD, children of group C had a non-classical form of 21-OHD. Four infants resulted heterozygotes and 4 children were wild-type. A girl clinically presenting a non-classical form of 21-OHD resulted compound heterozygote with one of the mutations not described in literature (R25W) and whose residual enzymatic activity is not already known. All affected children presented a 17-OHP level after ACTH stimulation greater than 100 nmol/l. We found an optimal concordance between 17-OHP levels after ACTH test and genotype. Conclusions: CYP21A2 analysis permitted to confirm the diagnosis of 21-OHD in 68% of our children. To improve this percentage we suggest to perform the CYP21A2 analysis only when 17-OHP after ACTH test is greater than 100 nmol/l. Moreover, we found an optimal genotype-phenotype concordance in the 21-OHD patients.

Possible andrologic markers in elevated neonatal 17-hydroxyprogesterone.

In this prospective study, we analyzed 30 male infants with increased neonatal 17-hydroxyprogesterone (17OH-P) (patients) and for comparison 52 age-matched healthy babies (control subjects) with the aim of investigating the hypothalamic-pituitary-testis axis in the first 6 months of life. Although T, FSH, and LH levels were not significantly different in patients and control subjects, inhibin B was higher in patients than in control subjects. Therefore we suggest a clinical follow-up of these babies during childhood and puberty to verify the evolution of their condition.

Children with premature pubarche: is an alterated neonatal 17-Ohp screening test a predictive factor?

BackgroundNeonatal screening for 21 hydroxylase deficiency is designed to detect classical form of congenital adrenal hyperplasia (CAH). It is still unclear whether newborns who result false positives at neonatal screening might later develop signs of androgen excess. The aim of this study is to verify whether a slightly elevated 17-OHP at newborn screening is a predictive factor for premature pubarche.MethodsWe evaluated all infants born between 2001 and 2014 with premature pubarche. In case of increased bone age, they were submitted to functional tests to find out the cause of their symptoms. Their 17-OHP values at newborn screening for CAH were reconsidered.ResultsWe identified 330 patients (269 females, 61 males) with premature pubarche. All these children had a normal 17-OHP at newborn screening with the exception of a child, born preterm and not affected by CAH.ConclusionsAn elevated 17-OHP at newborn screening is not a predictive factor for premature pubarche. A likely cause of increased 17-OHP level at screening is an immaturity of adrenal gland or a neonatal stress. Therefore a strict follow up of these neonates during childhood is not necessary.