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Biomedical subjects

William Reardon

Publications and source records attributed to William Reardon.

At least 19 recordsLinked to original sources
PubMed2007

FGF10 missense mutations in aplasia of lacrimal and salivary glands (ALSG).

Aplasia of lacrimal and salivary glands (ALSG) is an autosomal dominant congenital anomaly characterized by aplasia, atresia or hypoplasia of the lacrimal and salivary systems. Affected individuals present with irritable eyes and dryness of the mouth with variable expressivity. Mutations in FGF10 were recently described in ALSG and in lacrimo-auriculo-dento-digital (LADD) syndrome which are overlapping clinical entities. We present here two families with ALSG associated with missense mutations (R80S and G138E, respectively) affecting highly conserved residues in FGF10. The clinical features of these patients further broaden the knowledge of FGF10-related phenotypes.

Amino Acid Sequence↗
PubMed2007

Rhombencephalosynapsis presenting antenatally with ventriculomegaly/hydrocephalus in a likely case of Gomez-López-Hernández syndrome.

Rhombencephalosynapsis is a rare cerebellar malformation that can be associated with anomalies of the cerebral hemispheres and variable degrees of neurodevelopmental delay. A syndromic association, comprising rhombencephalosynapsis, developmental delay, scalp alopecia and trigeminal anaesthesia (Gomez-López-Hernández syndrome) has been described in seven individuals. We report the case of a 2-year-old boy with rhombencephalosynapsis, and review the evidence for a possible diagnosis of Gomez-López-Hernández syndrome. We also discuss other malformations reported in combination with rhombencephalosynapsis, and consider the possibility that a genetic aetiology for syndromic and nonsyndromic forms of rhombencephalosynapsis may be established with more detailed clinical and genetic studies.

Craniofacial Abnormalities↗
PubMed2006

Symptomatic anal anomalies in chromosome 22q11 deletion syndrome: a report of three patients.

Deletion of chromosome 22q11 is a common genetic condition with varying clinical presentation ranging from neonatal fatality to patients whose presentation to medical services will be prompted after a few years by speech delay or mild developmental concerns. While most published data relating to patients with 22q11 deletions has focused on the "classical" presentation of the condition with cardiac manifestations, hypocalcaemia and velopharyngeal insufficiency, a much wider range of clinical presentations can characterise this syndrome. Anal anomalies, comprising imperforate anus and symptomatic anal stenosis, are a rarely described presentation of this multisystem disorder. In this report we document three patients presenting to paediatric services with symptoms attributed initially to symptomatic anal stenosis/atresia.

Anal Canal↗
PubMed2006

The spectrum of congenital cardiac malformations encountered in six children with Kabuki syndrome.

We investigated the prevalence and forms of congenital cardiac malformations in six children with Kabuki syndrome. There were three girls and three boys, diagnosed at a median age of 1.7 years, with a range from 0.7 to 11.1 years. Cardiac lesions were present in five children (83%), specifically complete transposition, tetralogy of Fallot, coarctation of the aorta, ventricular septal defect, and patency of the arterial duct. Characteristic dysmorphic findings were noted in all patients, as well as a strong predisposition to severe problems with feeding in the neonatal period, and developmental delay. Cardiologists should be alert to this syndrome in children who present with the aforementioned constellation of findings, as patients with mild expression of Kabuki syndrome may go unrecognized for a considerable time.

Abnormalities, Multiple↗
PubMed2006

The tale of a nail sign in chromosome 4q34 deletion syndrome.

Relatively, few reports of deletions involving the distal long arm of chromosome 4 (4q) exist. Five further cases are described and the findings are compared with those in previous literature reports. Distal 4q deletions may be recognized by the distinctive appearance of the fifth finger, which is stiff with a hypoplastic distal phalanx and a hooked or volar nail. All cases with this characteristic fifth finger anomaly appear to have deletions involving 4q34.

Abnormalities, Multiple↗
PubMed2005

Asplenia in ATR-X syndrome: a second report.

Mutation at the ATR-X locus is associated with severe mental retardation. Several conditions, initially reported as clinically distinct phenotypes, have now been attributed to ATR-X mutation. Asplenia, in association with severe mental retardation, has been reported and subsequently demonstrated in one family to be due to ATR-X mutation. We now report on a second instance of a patient presenting with mental retardation and asplenia who has been shown to have a mutation at the ATR-X locus.

Abnormalities, Multiple↗
PubMed2005

Diversity and function of mutations in p450 oxidoreductase in patients with Antley-Bixler syndrome and disordered steroidogenesis.

P450 oxidoreductase (POR) is the obligatory flavoprotein intermediate that transfers electrons from reduced nicotinamide adenine dinucleotide phosphate (NADPH) to all microsomal cytochrome P450 enzymes. Although mouse Por gene ablation causes embryonic lethality, POR missense mutations cause disordered steroidogenesis, ambiguous genitalia, and Antley-Bixler syndrome (ABS), which has also been attributed to fibroblast growth factor receptor 2 (FGFR2) mutations. We sequenced the POR gene and FGFR2 exons 8 and 10 in 32 individuals with ABS and/or hormonal findings that suggested POR deficiency. POR and FGFR2 mutations segregated completely. Fifteen patients carried POR mutations on both alleles, 4 carried mutations on only one allele, 10 carried FGFR2 or FGFR3 mutations, and 3 patients carried no mutations. The 34 affected POR alleles included 10 with A287P (all from whites) and 7 with R457H (four Japanese, one African, two whites); 17 of the 34 alleles carried 16 "private" mutations, including 9 missense and 7 frameshift mutations. These 11 missense mutations, plus 10 others found in databases or reported elsewhere, were recreated by site-directed mutagenesis and were assessed by four assays: reduction of cytochrome c, oxidation of NADPH, support of 17alpha-hydroxylase activity, and support of 17,20 lyase using human P450c17. Assays that were based on cytochrome c, which is not a physiologic substrate for POR, correlated poorly with clinical phenotype, but assays that were based on POR's support of catalysis by P450c17--the enzyme most closely associated with the hormonal phenotype--provided an excellent genotype/phenotype correlation. Our large survey of patients with ABS shows that individuals with an ABS-like phenotype and normal steroidogenesis have FGFR mutations, whereas those with ambiguous genitalia and disordered steroidogenesis should be recognized as having a distinct new disease: POR deficiency.

Abnormalities, Multiple↗
PubMed2005

Twenty-six novel EFNB1 mutations in familial and sporadic craniofrontonasal syndrome (CFNS).

Craniofrontonasal syndrome (CFNS) is an X-linked disorder characterized by a more severe manifestation in heterozygous females than in hemizygous males. Heterozygous females have craniofrontonasal dysplasia (CFND) and occasionally extracranial manifestations including midline defects and skeletal abnormalities, whereas hemizygous males show no or only mild features such as hypertelorism and rarely show cleft lip or palate. Mutations in the EFNB1 gene in Xq12 are responsible for familial and sporadic CFNS. The EFNB1 gene encodes ephrin-B1, a transmembrane ligand that also exhibits receptor-like effects. We performed mutation analysis in nine unrelated families and 29 sporadic patients with CFNS. DNA sequencing revealed mutations in 33 (86.8%) cases including 26 distinct novel mutations. A recurrent nonsense mutation, c.196C>T/R66X, was detected in one family and four sporadic patients. The majority of mutations (26/33) were located in exons 2 and 3 of the EFNB1 gene encoding the extracellular ephrin domain. The mutation spectrum includes frameshift, nonsense, missense, and splice site mutations, with a predominance of frameshift and nonsense mutations resulting in premature truncation codons. For the first time we describe mutations in exons 4 and 5 of EFNB1. Of particular interest are the frameshift mutations located in the last 25 codons of EFNB1 encoding the carboxyterminal end of ephrin-B1. They result in an extension by 44 residues. These mutations disrupt the intracellular binding sites for Grb4 and PDZ-effector proteins involved in reverse signaling. We conclude that the major causes of familial as well as sporadic CFNS are loss of function mutations in the EFNB1 gene that comprise premature termination or abrogate receptor-ligand interaction, oligomerization, and ephrin-B1 reverse signaling.

Amino Acid Sequence↗
PubMed2005

Molecular characterisation of patients with subtelomeric 22q abnormalities using chromosome specific array-based comparative genomic hybridisation.

The 22q13 deletion syndrome is associated with global developmental delay, absent or delayed speech, and generalised hypotonia. In this study, the size and nature of 22q13 deletions (n=9) were studied in detail by high-resolution chromosome specific array-based comparative genomic hybridisation (array CGH). The deletion sizes varied considerably between the different patients, that is, the largest deletion spanning 8.4 Mb with the breakpoint mapping to 22q13.2 and the smallest deletion spanning 3.3 Mb with the breakpoint mapping to 22q13.31. In one case, a unique subtelomeric 3.9 Mb deletion associated with a 2.0 Mb duplication of 22q13 was observed, adding to a growing number of similar cases identified for other chromosome ends. Remarkably, this patient had signs suggestive of retinitis pigmentosa, which has never been reported before in the 22q13 deletion syndrome. The identification of two pairs of recurrent proximal breakpoints on 22q13 suggests that these specific regions may be prone to recombination, due to yet unknown genome architectural features. In addition to the copy number changes on 22q13, a duplication of approximately 330 kb on 22q11.1 was observed and shown to be a genetic large-scale copy number variation without clinical consequences. The current study failed to reveal relationships between the clinical features and the deletion sizes. Global developmental delay and absent or severely delayed speech were observed in all patients, whereas hypotonia was present in 89% of the cases (8/9). This study underscores the utility of array CGH for characterising the size and nature of subtelomeric deletions, such as monosomy 22q13, and underlines the considerable variability in deletion size in the 22q13 deletion syndrome regardless of the clinical phenotype.

Adolescent↗
PubMed2005

Assisted reproduction technology and defects of genomic imprinting.

It is estimated that approximately 1% of the newborn population of the British Isles are conceived following assisted reproduction technologies such as in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI). While the long term outcome of IVF children is mostly reassuring, some concerns remain. Specifically, recent studies have suggested a possible association between assisted conception and clinical conditions of genetic origin known as genomic imprinting defects. This has arisen from several different studies observing an excess of assisted conceptions among the rare clinical disorders of Beckwith-Wiedemann syndrome (BWS) and Angelman syndrome (AS). The numbers of such patients described in the studies to date are small but indicate a clear need for large-scale investigations to clarify the link between genomic imprinting defects and assisted conception as well as to establish the exact biological basis of any such link. In view of the strong public interest in this area of medicine, it behoves all professionals working in reproductive medicine and associated areas to be aware of these emerging data and be in a position to discuss them in as informed and responsible a manner with patients, as current data limitations permit.

Beckwith-Wiedemann Syndrome↗
PubMed2004

Septo-optic dysplasia with digital anomalies--a recurrent pattern syndrome.

A distinct form of septo-optic dysplasia (SOD) comprises limb malformations in addition to the characteristic CNS and ocular abnormalities. To date, there have been 4 reports, citing 5 affected patients with this combined phenotype. We now add a further case and present neuroradiological images of the CNS findings in this condition. The striking consistency of the limb malformations and their overlap with the Streeter's band phenotype is emphasized.

Abnormalities, Multiple↗
PubMed2004

Congenital cardiac disease as a core feature of cranio-osteoarthropathy.

Cranio-osteoarthropathy is a rare condition. Classically, signs are identifiable in infancy with clubbing of fingers, and delayed closure of the clinically enlarged cranial sutures, followed by periosteal new bone formation on X-rays of the long bones. Ultimately, joint swelling and stiffness follow, typically involving the large joints. We report two unrelated patients with features of cranio-osteoarthropathy, both of whom also had a history of congenital heart disease. Moreover, the cases reported here, manifesting significant differences in radiological features, emphasize the variability of radiological findings which can attend this condition.

Ankle↗
PubMed2003

Moebius sequence and hypogonadotrophic hypogonadism.

A distinct form of Moebius sequence is associated with hypogonadotrophic hypogonadism. There have been five such cases to date. We now add a further case with detailed neurologic, endocrine, and autopsy findings and offer a hypothesis drawing parallels with the already established basis of hypogonadotrophic hypogonadism in the X-linked form of Kallman syndrome.

Cranial Nerve Diseases↗
PubMed2003

Congenital ptosis with esotropia in brothers.

Two brothers are reported with congenital ptosis and esotropia, one of whom also has polythelia. This particular constellation of clinical features has not previously been described, although comparison with recorded families does show significant overlap with the pedigree reported by Frydman et al.

Blepharoptosis↗
PubMed2002

Okihiro syndrome is caused by SALL4 mutations.

Okihiro syndrome refers to the association of forearm malformations with Duane syndrome of eye retraction. Based on the reported literature experience, clinical diagnosis of the syndrome can be elusive, owing to the variable presentation in families reported. Specifically, there is overlap of clinical features with other conditions, most notably Holt-Oram syndrome, a condition resulting from mutation of the TBX5 locus and Townes-Brocks syndrome, known to be caused by mutations in the SALL1 gene. Arising from our observation of several malformations in Okihiro syndrome patients which are also described in Townes-Brocks syndrome, we postulated that Okihiro syndrome might result from mutation of another member of the human SALL gene family. We have characterized the human SALL4 gene on chromosome 20q13.13-q13.2. Moreover, we have identified literature reports of forelimb malformations in patients with cytogenetically identifiable abnormalities of this region. We here present evidence in 5 of 8 affected families that mutation at this locus results in the Okihiro syndrome phenotype.

Case-Control Studies↗
PubMed2002

Genitopatellar syndrome: a recognizable phenotype.

Genitopatellar syndrome is a newly described condition, subject of a single literature report to date. The condition comprises absent patellae, genital and renal malformations, joint dislocation, and mental retardation. Recurrence has been recorded in two kindreds, consistent with autosomal recessive inheritance.

Abnormalities, Multiple↗