Nail‐Patella Syndrome with an Emphasis on the Risk of Renal and Ocular Findings

Abstract: We describe a 6‐year‐old girl presenting with nail dysplasia affecting all nails and hands for 2 years. Changes were seen on the ulnar side of the nails. She was assessed for limitation of elbow movements at 3 weeks of age and underwent physiotherapy for thickened biceps tendon. She subsequently developed laxity of knees and ankles, and x‐ray revealed absent patellae at 32 weeks. She had behavioral abnormalities and sleep disturbances. X‐ray of the pelvis revealed iliac horns, and urinalysis showed 3+ proteinuria. She had mixed hyperlipidemia. Her chromosomal analysis was normal but showed a mutation in the LMX1B gene. She was diagnosed to have Nail‐patella syndrome or Hereditary osteo‐onychodysplasia (HOOD Syndrome). Her renal imaging was normal, as were her ocular pressures. She is under regular surveillance by a multi‐disciplinary team of genetic counselors, orthopedists, rheumatologists and ophthalmologists. She is currently prescribed enalapril, melatonin and simvastatin.     

X‐linked hereditary motor sensory neuropathy (type 1) presenting with a stroke‐like episode

X‐linked hereditary motor sensory neuropathy type 1 (CMTX 1) is caused by mutation in the GJB1 gene that codes for the connexin 32 protein. Central nervous system involvement with or without white matter changes on magnetic resonance imaging (MRI) has rarely been reported in this condition. We report the case of a 7‐year‐old, previously well male who presented with a stroke‐like episode that manifested as left hemiparesis and dysphasia. An initial brain MRI showed white matter signal changes affecting the corpus callosum and periventricular areas with a posterior predominance. Our patient made a complete clinical recovery in 36 hours. Clinical examination at this stage showed no evidence of a peripheral neuropathy. A repeat brain MRI 6 weeks later showed almost complete resolution of the changes seen initially. Subsequent investigations showed a Val177Ala mutation in the GJB1 gene. This mutation has so far not been described in the Caucasian population and has been only described once before. Electrophysiological studies showed a mixed demyelinating and axonal sensorimotor neuropathy in keeping with CMTX 1. Five months after the initial presentation our patient developed clinical evidence of a peripheral neuropathy in the form of absent ankle reflexes, weak dorsiflexors, and evertors of both feet.     

Ablation of Idiopathic Right Ventricular Outflow Tract Tachycardia: Current Perspectives

Ventricular tachycardia (VT) arising from the right ventricular outflow tract (RVOT) in the absence of overt structural heart disease is a common entity. Exclusion of occult structural disease such as arrhythmogenic right ventricular cardiomyopathy is critical as this diagnosis impacts both ablation outcomes and long-term prognosis. VT is most commonly due to triggered activity. Induction of the target arrhythmia in the laboratory is often problematic, and is frequently facilitated by catecholamine infusion. Recent data indicate that high-density three-dimensional activation mapping facilitates identification of target sites for ablation, and that the spatial resolution of pacemapping may be more limited than previously recognized. A standard 12-lead electrocardiogram is useful in providing an initial approximation of the site of origin within the outflow tract, and may contain subtle clues to potentially confounding foci on the left ventricular endocardial or epicardial surface. When sufficient arrhythmia is present to permit mapping, successful ablation can be expected in 90–95% of patients, with a recurrence risk of approximately 5%. In experienced centers, major complications are ≤1% and outcomes should approach those obtained for the common forms of supraventricular tachycardia.