Clinical and molecular heterogeneity of syndromic hypothalamic hamartoma.

Two children are presented who have a distinct syndrome of multiple buccolingual frenula, a stiff and short fifth finger with small nails, a hypothalamic hamartoma, mild to moderate neurological impairment, and mild endocrinological symptoms. No variant assessed to be pathogenic or likely pathogenic was detected in the GLI3 gene in either child. This syndrome appears to be distinct from the inherited Pallister-Hall syndrome associated with GLI3 variants, which is characterized by hypothalamic hamartoma, mesoaxial polydactyly, and other anomalies. In the individuals described here, manifestations outside of the central nervous system were milder and the mesoaxial polydactyly, which is common in individuals with Pallister-Hall syndrome, was absent. Instead, these children had multiple buccolingual frenula together with the unusual appearance of the fifth digit. It remains unclear whether these two individuals represent a separate nosologic entity or if they represent a milder manifestation of one of the more severe syndromes associated with a hypothalamic hamartoma.

Postmortem Genetic Testing for Cardiac Ion Channelopathies in Stillbirths.

BACKGROUND: Although stillbirth is a significant health problem worldwide, the definitive cause of death remains elusive in many cases, despite detailed autopsy. In this study of partly explained and unexplained stillbirths, we used next-generation sequencing to examine an extended panel of 35 candidate genes known to be associated with ion channel disorders and sudden cardiac death. METHODS AND RESULTS: We examined tissue from 242 stillbirths (≥22 weeks), including those where no definite cause of death could be confirmed after a full autopsy. We obtained high-quality DNA from 70 cases, which were then sequenced for a custom panel of 35 genes, 12 for inherited long- and short-QT syndrome genes (LQT1-LQT12 and SQT1-3), and 23 additional candidate genes derived from genome-wide association studies. We examined the functional significance of a selected variant by patch-clamp electrophysiological recording. No predicted damaging variants were identified in KCNQ1 (LQT1) or KCNH2 (LQT2). A rare putative pathogenic variant was found in KCNJ2(LQT7) in 1 case, and several novel variants of uncertain significance were observed. The KCNJ2 variant (p. R40Q), when assessed by whole-cell patch clamp, affected the function of the channel. There was no significant evidence of enrichment of rare predicted damaging variants within any of the candidate genes. CONCLUSIONS: Although a causative link is unclear, 1 putative pathogenic and variants of uncertain significance variant resulting in cardiac channelopathies was identified in some cases of otherwise unexplained stillbirth, and these variants may have a role in fetal demise. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01120886.

Antenatally Detected Congenital Pulmonary Airway Malformations: The Oxford Experience.

Congenital airway pulmonary malformations are increasingly being diagnosed, but their management continues to remain controversial. Our approach has been to offer surgery to mitigate the risk of infection and possible malignancy. All patients routinely undergo a CT scan of the chest postnatally and once the diagnosis is confirmed, minimal access surgery is offered. Our anesthetists provide single-lung ventilation to enhance the operative view. We conducted a retrospective review over a 10-year period, during which 91 patients were prenatally suspected to have a cystic lung lesion. There were 88 live births of which 29 (33%) cases were initially managed conservatively based on CT findings. Five of these patients, however, became symptomatic needing surgery. A total of 64 (73%) patients underwent surgery with the most common lesions being congenital pulmonary airway malformations (CPAMs) (24), hybrid lesions (19), and pulmonary sequestrations (12). The median age at surgery was 5 months (1 day to 17 months). Using a minimal access approach, 41 (64%) cases were completed with 17 performed open from the onset. Open surgery was indicated in neonates who became symptomatic within the first few weeks of life as well as patients in respiratory distress that would not tolerate either single-lung ventilation or gas insufflation. There were six further conversions to open from minimal access surgery due to poor visualization or technical difficulties. One patient needed a perioperative blood transfusion and one patient had a more prolonged stay due to persistent air leak managed conservatively. Among asymptomatic patients, evidence of microscopic disease was seen, which included infection as well as two cases of tumors, one pleuropulmonary blastoma seen as part of a CPAM, and one rhabdomyomatous dysplasia seen in the CPAM component of a hybrid lesion. In our experience, excising asymptomatic lesions is safe with minimal complications. Single-lung ventilation in combination with thoracoscopy provides excellent vision. There is a risk of infection and a definite, albeit low, risk of malignancy, which may outweigh the benefits of conservative management.

The pathology of congenital lung lesions.

The spectrum of complications associated with congenital lung malformation is wide. They can range from fetal hydrops in utero to postnatal problems of ventilation, obstruction and infection; presentation may occur from the neonatal period to adulthood. Many lesions will remain asymptomatic while at the other end of the complication spectrum, there is a small risk of neoplasia associated with some forms of cystic lung. A better understanding of the pathology has shown that bronchial atresia/obstruction is the likely hidden pathology underlying many congenital lung lesions leading to downstream cystic maldevelopment. Earlier diagnosis has led to increasing difficulties in ascribing malformations to conventional categories that were originally described in postnatal lungs. It is probably more important to be aware of the potential combination of vascular and airway connections and complications than to try and prescribe a classification of pulmonary lesions associated with rigid definitions.

Eculizumab therapy for atypical haemolytic uraemic syndrome due to a gain-of-function mutation of complement factor B.

BACKGROUND: Atypical haemolytic uraemic syndrome (aHUS) is caused by dysregulated complement activation. A humanised anti-C5 monoclonal antibody has recently become available for treatment of this condition CASE-DIAGNOSIS/TREATMENT: We present the first description of an infant with an activating mutation of complement factor B successfully treated with eculizumab. On standard doses she had evidence of ongoing C5 cleavage despite a good clinical response. CONCLUSIONS: Eculizumab is effective therapy for aHUS associated with factor B mutations, but recommended doses may not be adequate for all patients.

Bilineal inheritance of PKD1 abnormalities mimicking autosomal recessive polycystic disease.

BACKGROUND: Dominant polycystic kidney disease is common and usually presents clinically in adulthood. Recessive polycystic kidney disease is much less common and frequently presents antenatally or in the neonatal period with severe renal involvement. These are usually thought of as clinically distinct entities but diagnostic confusion is not infrequent. CASE-DIAGNOSIS/TREATMENT: We describe an infant with antenatally diagnosed massive renal enlargement and oligohydramnios with no resolvable cysts on ultrasound scanning. He underwent bilateral nephrectomy because of respiratory compromise and poor renal function but died subsequently of overwhelming sepsis. Genetic analysis revealed that he had bilineal inheritance of abnormalities of PKD1 and no demonstrable abnormalities of PKD2 or PKHD1. CONCLUSIONS: Biallelic inheritance of abnormalities of PKD1 may causextremely severe disease resembling autosomal recessive polycystic kidney disease (ARPKD) which can result indiagnostic confusion. Accurate diagnosis is essential forgenetic counseling [corrected].

Cisplatin-induced haemolytic uraemic syndrome associated with a novel intronic mutation of CD46 treated with eculizumab.

A 2-year-old patient with a neuroblastoma developed haemolytic uraemic syndrome (HUS) following treatment with cisplatin and carboplatin. Following treatment with eculizumab, there was a substantial improvement in renal function with the recovery of the platelet count and the cessation of haemolysis. Subsequent investigations showed a novel, heterozygous CD46 splice site mutation with reduced peripheral blood neutrophil CD46 expression. Withdrawal of eculizumab was followed by the recurrence of disease activity, which resolved with re-introduction of therapy. Abnormal regulation of complement may be associated with other cases of cisplatin-induced HUS and treatment with eculizumab may be appropriate for other affected individuals.

Exome analysis resolves differential diagnosis of familial kidney disease and uncovers a potential confounding variant.

A girl aged 6 presented with haematuria and her sister (aged 5) presented with haematuria and proteinuria. Family history showed multiple individuals suffering from end stage renal failure from the paternal side of the pedigree. Following kidney biopsy in the father and paternal grandmother, the pathological diagnosis was of focal segmental glomerulosclerosis (FSGS). Exome sequencing was undertaken in the proband's sister and grandmother. Genetic variants shared by both affected individuals were interrogated to identify the genetic cause of disease. Candidate variants were then sequenced in all the family members to determine segregation with the disease. A mutation of COL4A5 known to cause Alport syndrome segregated with disease from the paternal side of the pedigree and a variant in NPHS1 was present in both paediatric cases and inherited from their mother. This study highlights the advantages of exome sequencing over single gene testing; disease presentation can be heterogeneous with several genes representing plausible candidates; candidate gene(s) may be unavailable as a diagnostic test; consecutive, single gene testing typically concludes once a single causal mutation is identified. In this family, we were able to confirm a diagnosis of Alport syndrome, which will facilitate testing in other family members.

The role of osteoblast cells in the pathogenesis of unicameral bone cysts.

PURPOSE: The pathogenesis of unicameral bone cysts (UBCs) remains largely unknown. Osteoclasts have been implicated, but the role of osteoblastic cells has, to date, not been explored. This study investigated the pathophysiology of UBCs by examining the interactions between the cyst fluid and human bone marrow stromal cells (hBMSCs) and the effect of the fluid on osteogenesis. METHODS: Fluid was aspirated from two UBCs and analysed for protein, electrolyte and cytokine levels. Graded concentrations of the fluid were used as culture media for hBMSCs to determine the effects of the fluid on hBMSC proliferation and osteogenic differentiation. The fibrocellular lining was analysed histologically and by electron microscopy. RESULTS: Alkaline phosphatase (ALP) staining of hBMSCs that were cultured in cyst fluid demonstrated increased cell proliferation and osteogenic differentiation compared to basal media controls. Biochemical analysis of these hBMSCs compared to basal controls confirmed a marked increase in DNA content (as a marker of proliferation) and ALP activity (as a marker of osteogenic differentiation) which was highly significant (p < 0.001). Osteoclasts were demonstrated in abundance in the cyst lining. The cyst fluid cytokine profile revealed levels of the pro-osteoclast cytokines IL-6, MIP-1α and MCP-1 that were 19×, 31× and 35× greater than those in reference serum. CONCLUSIONS: Cyst fluid promoted osteoblastic growth and differentiation. Despite appearing paradoxical that the cyst fluid promoted osteogenesis, osteoblastic cells are required for osteoclastogenesis through RANKL signalling. Three key cytokines in this pathway (IL-6, MIP-1α, MCP-1) were highly elevated in cyst fluid. These findings may hold the key to the pathogenesis of UBCs, with implications for treatment methods.

Indications and outcomes of deep anterior lamellar keratoplasty in children.

PURPOSE: To report our experience of deep anterior lamellar keratoplasty (DALK) in children. DESIGN: Retrospective case note review. PARTICIPANTS: Nine patients (13 eyes) aged from 13 weeks to 14 years, 11 months at the Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children National Health Service (NHS) Trust, London, United Kingdom. METHODS: A study of all pediatric patients undergoing DALK from February 2002 to October 2008 was undertaken. Deep anterior lamellar keratoplasty was attempted in 9 children (13 eyes); the procedure was successful in 11 eyes, and 2 eyes progressed to penetrating keratoplasty (PKP). One eye underwent repeat DALK. Preoperative examination included electrophysiology, ultrasound biomicroscopy (UBM), and slit-lamp biomicroscopy. MAIN OUTCOME MEASURES: Complications and visual acuity at last follow-up. RESULTS: Five patients had mucopolysaccharidoses (MPS), 3 patients had scarring presumed to be infectious, and 1 patient had keratoconus. Because of the failure of follow-up and loose sutures, 1 child with MPS had an epithelial rejection and the operation was repeated successfully. All grafts showed good graft clarity 10 to 80 months after grafting with visual acuities ranging from 0.28 to 1.0 logarithm of the minimum angle of resolution. Two children with nonspecific causes of scarring showed good visual acuities 24 to 51 months post-DALK. Two children who had conversion to PKP were lost to follow-up because they had moved abroad. In 4 of the 5 children with MPS, established techniques of DALK could not be performed because of excessive glycosaminoglycans (GAGs) in the stroma. Ultrasound biomicroscopy was used to guide trephination depth in the first instance. In 1 child with MPS, viscodissection was successfully used. All clinically diagnosed scars were histologically confirmed, and electron microscopy of corneal buttons confirmed the diagnosis in patients with MPS. CONCLUSIONS: Deep anterior lamellar keratoplasty should be considered in children with MPS and partial-thickness scars. In MPS, viscodissection and the "big bubble" technique may not be useful if there are excessive GAGs in the stroma. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Ophthalmological aspects of Pierson syndrome.

PURPOSE: To study the ocular phenotype of Pierson syndrome and to increase awareness among ophthalmologists of the diagnostic features of this condition. DESIGN: Retrospective, observational case series. METHODS: A multicenter study of 17 patients with molecularly confirmed Pierson syndrome. The eye findings were reviewed and compared to pertinent findings from the literature. RESULTS: The most characteristic ocular anomaly was microcoria. A wide range of additional abnormalities were found, including posterior embryotoxon, megalocornea, iris hypoplasia, cataract, abnormal lens shape, posterior lenticonus, persistent fetal vasculature, retinal detachment, variable axial lengths, and glaucoma. There was high interocular and intrafamilial variability. CONCLUSIONS: Loss-of-function mutations in laminin beta2 (LAMB2) cause a broad range of ocular pathology, emphasizing the importance of laminin beta2 in eye development. Patients with Pierson syndrome can initially present with ocular signs alone. In newborns with marked bilateral microcoria, Pierson syndrome should be considered and renal function investigated.