Enzyme replacement therapy (ERT) is available for mucopolysaccharidosis (MPS) I, MPS II, MPS VI, and MPS IVA. The efficacy of ERT has been evaluated in clinical trials and in many post-marketing studies with a long-term follow-up for MPS I, MPS II, and MPS VI. While ERT is effective in reducing urinary glycosaminoglycans (GAGs) and liver and spleen volume, cartilaginous organs such as the trachea and bronchi, bones and eyes are poorly impacted by ERT probably due to limited penetration in the specific tissue. ERT in the present formulations also does not cross the blood–brain barrier, with the consequence that the central nervous system is not cured by ERT. This is particularly important for severe forms of MPS I and MPS II characterized by cognitive decline. For severe MPS I patients (Hurler), early haematopoietic stem cell transplantation is the gold standard, while still controversial is the role of stem cell transplantation in MPS II. The use of ERT in patients with severe cognitive decline is the subject of debate; the current position of the scientific community is that ERT must be started in all patients who do not have a more effective treatment. Neonatal screening is widely suggested for treatable MPS, and many pilot studies are ongoing. The rationale is that early, possibly pre-symptomatic treatment can improve prognosis. All patients develop anti-ERT antibodies but only a few have drug-related adverse reactions. It has not yet been definitely clarified if high-titre antibodies may, at least in some cases, reduce the efficacy of ERT.
Next-generation sequencing is a straightforward tool for the identification of disease genes in extended genomic regions. Autozygosity mapping was performed on a five-generation inbred Italian family with three siblings affected with Clericuzio-type poikiloderma with neutropenia (PN [MIM %604173]), a rare autosomal-recessive genodermatosis characterised by poikiloderma, pachyonychia, and chronic neutropenia. The siblings were initially diagnosed as affected with Rothmund-Thomson syndrome (RTS [MIM #268400]), with which PN shows phenotypic overlap. Linkage analysis on all living subjects of the family identified a large 16q region inherited identically by descent (IBD) in all affected family members. Deep sequencing of this 3.4 Mb region previously enriched with array capture revealed a homozygous c.504-2 A>C mismatch in all affected siblings. The mutation destroys the invariant AG acceptor site of intron 4 of the evolutionarily conserved C16orf57 gene. Two distinct deleterious mutations (c.502A>G and c.666_676+1del12) identified in an unrelated PN patient confirmed that the C16orf57 gene is responsible for PN. The function of the predicted C16orf57 gene is unknown, but its product has been shown to be interconnected to RECQL4 protein via SMAD4 proteins. The unravelled clinical and genetic identity of PN allows patients to undergo genetic testing and follow-up.
T he insulin-like growth factors (IGFs; somatomedins) comprise a family of peptides that play important roles in mammalian growth and development. The principal members of this family are IGF1 and IGF2. IGF1 (somatomedin C), a 70 residue basic polypeptide, mediates many of the growth promoting actions of growth hormone (GH) and has metabolic and mitogenic effects.1 The major source of circulating IGF1 is the liver, but it is also produced in a wide variety of tissues and has endocrine and paracrine modes of action. The mature IGF1 peptide has A, B, C, and D domains with homology to insulin, and is highly conserved.2 It is produced as an inactive precursor, pre-pro-IGF1, with an additional carboxyterminal E region that plays an important role in the maturation of normal IGF1 peptide. This regulatory region is obtained by alternative splicing of the last two exons. IGF1 resides on the long arm of chromosome 12 (12q 22-24.1), 3 and several molecular studies have demonstrated that the structure of this gene is very complex. The gene contains six exons, which extend over more than 85 kb on chromosomal DNA. For human IGF1, two potential primary translation products exist: IGF1A and IGF1B, with sizes of 153 and 195 amino acids respectively. The two precursors are synthesised from distinct messenger RNAs produced by alternative splicing of the primary transcript. IGF1A mRNA contains exons 1, 2, 3, 4, and 6 of the human IGF1 gene while IGF1B is encoded by exons 1, 2, 3, 4, and 5. It has been speculated that IGF1B plays the major role during intrauterine growth, while the same function during postnatal growth is taken over by IGF1A. 4 Recent studies have focused attention on the genetic causes of growth alterations. Mutations involving the molecular structure of GH 5 or the function of the GH receptor 6 have been described. Recently, a partial deletion of the gene for IGF1, resulting in intrauterine growth failure plus severe post-natal growth retardation, sensorineural deafness, and mental retardation has been found. 7 In this study, we describe a new case of IGF1 deficiency associated with sensorineural deafness, severe pre-and post-natal growth failure, and delayed psychomotor development produced by a novel transversion TRA, which disrupts the normal consensus sequence for the polyadenylation site in the 39 untranslated region of exon 6 of IGF1, leading to altered mRNA processing, which could account for the extremely low IGF1 circulating levels and for the clinical findings. METHODS Case reportThe patient was born at 39 weeks' gestation by caesarean section because of poor fetal growth. The pregnancy had until then been uneventful. The birth weight was 1480 kg (24SD), length was 41 cm (26.5 SD), and the head circumference was 26.5 cm (,5th percentile). Hypoglycaemia and icterus were not reported. His parents were second cousins and the family history showed several miscarriages. His mother was 153 cm tall (5th percentile) and his father was 163 cm (5th percentile). His healthy sister, at the age of 9 years, was ...
The spectrum of brain and spine MRI abnormalities in Hunter disease is extremely wide and requires a thorough evaluation. WMAs, atrophy/communicating hydrocephalus and spinal stenosis progress over time and might represent possible disease severity markers for new treatment efficacy assessment.
Aim: The aim of the study was to investigate the frequency of breastfeeding among children with Down syndrome. Methods: The mothers of 560 children with Down syndrome attending four university hospitals in Italy were interviewed and the neonatal clinical records retrieved. Information was collected on the type of infant feeding and on why some mothers had not breastfed their children. Two groups of healthy children whose feeding habits had been previously investigated were recruited as control subjects (1601 and 714, respectively). A paediatrician in each hospital was interviewed about the neonatal admission policy of children with Down syndrome. Results: Among the 560 Down children, 246 (44%) were admitted to the neonatal unit. Compared with the two control groups, children with Down syndrome were significantly more frequently bottle‐fed (57% vs 15% and 24%, respectively, odds ratio 7.5, 95% CI 6.0–9.4 and 4.2, 95% CI 3.3–5.4. respectively). Only 30% of infants admitted to the neonatal unit were breastfed. The main reasons reported by the mothers for not having breastfed were infants’illness in infants who had been admitted to the neonatal unit and frustration or depression, perceived milk insufficiency and difficulty with suckling for those babies who had not been admitted to the unit. The paediatricians reported that the admission of a baby with Down syndrome to the neonatal unit could sometimes take place not for medical reasons, but for diagnostic work‐up or for a more appropriate diagnosis and to maintain communication with the family. Conclusions: Down syndrome babies are less frequently breastfed compared with healthy children. Support in breastfeeding should become a relevant point of health supervision for children with Down syndrome.
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