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Biomedical subjects

Padraic Grattan-Smith

Publications and source records attributed to Padraic Grattan-Smith.

6 recordsLinked to original sources

Defective p53 response and apoptosis associated with an ataxia-telangiectasia-like phenotype.

Ataxia-telangiectasia mutated (ATM), the protein defective in ataxia-telangiectasia, plays a central role in DNA damage response and signaling to cell cycle checkpoints. We describe here a cell line from a patient with an ataxia-telangiectasia-like clinical phenotype defective in the p53 response to radiation but with normal ATM activation and efficient downstream phosphorylation of other ATM substrates. No mutations were detected in ATM cDNA. A normal level of interaction between p53 and peptidyl-prolyl-isomerase Pin1 suggests that posttranslational modification was intact in these cells but operating at reduced level. Defective p53 stabilization was accompanied by defective induction of p53 effector genes and failure to induce apoptosis in response to DNA-damaging agents. Continued association between p53 and murine double minute-2 (Mdm2) occurred in irradiated ATL2ABR cells in response to DNA damage, and incubation with Mdm2 antagonists, nutlins, increased the stabilization of p53 and its transcriptional activity but failed to induce apoptosis. These results suggest that ATM-dependent stabilization of p53 and induction of apoptosis by radiation involve an additional factor(s) that is defective in ATL2ABR cells.

Apoptosis↗

Movement disorder emergencies.

Movement disorders may present acutely, and failure to recognize and exclude important differential diagnoses can result in significant morbidity or mortality. Unfortunately, much of the literature pertaining to this topic is scattered and not easily accessible. This review aims to address this deficit. Movement disorder emergencies are discussed according to their most likely mode of presentation. Diagnostic considerations and early management principles are reviewed, along with appropriate pathophysiology where relevant.

Acute Disease↗

Neuroepithelial cysts in a patient with Joubert syndrome plus renal cysts.

Joubert syndrome is a rare genetic neurologic disorder associated with hypoplasia or absence of the cerebellar vermis. The classic form is characterized by ataxia, hypotonia, eye movement abnormalities, developmental delay, and abnormal breathing patterns. In contrast, other patients have the additional feature of kidney cysts. This population could represent a distinct form of Joubert syndrome. One case of Joubert syndrome with subcortical neuroepithelial cysts was recently described. We report a new case of Joubert syndrome with overlapping features, including diffuse progressive central nervous system neuroepithelial cysts and kidney cysts. Our data suggest that neuroepithelial cysts occur in conjunction with Joubert syndrome associated with kidney cysts.

Brain Diseases↗

Infantile spinal muscular atrophy with respiratory distress type 1 (SMARD1).

Autosomal recessive spinal muscular atrophy with respiratory distress type 1 (SMARD1) is the second anterior horn cell disease in infants in which the genetic defect has been defined. SMARD1 results from mutations in the gene encoding the immunoglobulin micro-binding protein 2 (IGHMBP2) on chromosome 11q13. Our aim was to review the clinical features of 29 infants affected with SMARD1 and report on 26 novel IGHMBP2 mutations. Intrauterine growth retardation, weak cry, and foot deformities were the earliest symptoms of SMARD1. Most patients presented at the age of 1 to 6 months with respiratory distress due to diaphragmatic paralysis and progressive muscle weakness with predominantly distal lower limb muscle involvement. Sensory and autonomic nerves are also affected. Because of the poor prognosis, there is a demand for prenatal diagnosis, and clear diagnostic criteria for infantile SMARD1 are needed. The diagnosis of SMARD1 should be considered in infants with non-5q spinal muscular atrophy, neuropathy, and muscle weakness and/or respiratory distress of unclear cause. Furthermore, consanguineous parents of a child with sudden infant death syndrome should be examined for IGHMBP2 mutations.

Carrier Proteins↗

Athetosis II: the syndrome of mild athetoid cerebral palsy.

We describe 8 patients who presented with continuous, irregular movements occurring independently in individual fingers and, in some cases, toes, in the setting of mild dystonia present since early childhood and not associated with major disability. The finger movements varied from low-amplitude quivering or wriggling to larger amplitude movements in the plane of abduction-adduction as well as flexion-extension; they were asymmetrical but not unilateral. Quivering or working of the facial muscles was seen in 5 patients. Most patients reported worsening of the movements over the years, but there was no other evidence of a progressive neurological disease. We classify the movement disorder as athetosis as described by Hammond and Shaw and the syndrome as mild athetoid cerebral palsy.

Adolescent↗