An investigation of the practice activities and coaching behaviors of professional top-level youth soccer coaches.

The aim of this study was to investigate the coaching behaviors of elite English youth soccer coaches in different practice settings and gain insight into the coaches' cognitive processes underpinning these behaviors. The practice setting was split into two types of activities, "training form" and "playing form," and behavioral data were collected using a modified version of the Coach Analysis and Intervention System. Interpretive interview data were triangulated with the behavioral data to ensure that both the "what" and the "why" of the coaches' behavior and practice were considered. The results showed the coaches using more "training form" activities than "playing form," and using high levels of prescriptive instruction, regardless of practice type, in contrast to a stated desire to "developing the whole player," creating "decision makers," and being a "facilitator of knowledge creation." The interviews revealed that the coaches had a low self-awareness about their behavior, with an epistemological gap identified between understanding and practice, with statements of intent not being matched by knowledge and action.

PAK3 mutation in nonsyndromic X-linked mental retardation.

Nonsyndromic X-linked mental retardation (MRX) syndromes are clinically homogeneous but genetically heterogeneous disorders, whose genetic bases are largely unknown. Affected individuals in a multiplex pedigree with MRX (MRX30), previously mapped to Xq22, show a point mutation in the PAK3 (p21-activated kinase) gene, which encodes a serine-threonine kinase. PAK proteins are crucial effectors linking Rho GTPases to cytoskeletal reorganization and to nuclear signalling. The mutation produces premature termination, disrupting kinase function. MRI analysis showed no gross defects in brain development. Immunofluorescence analysis showed that PAK3 protein is highly expressed in postmitotic neurons of the developing and postnatal cerebral cortex and hippocampus. Signal transduction through Rho GTPases and PAK3 may be critical for human cognitive function.

Fragile X syndrome without CCG amplification has an FMR1 deletion.

We describe a patient with typical clinical features of the fragile X syndrome, but without cytogenetic expression of the fragile X or an amplified CCG trinucleotide repeat fragment. The patient has a previously uncharacterized submicroscopic deletion encompassing the CCG repeat, the entire FMR1 gene and about 2.5 megabases of flanking sequences. This finding confirms that the fragile X phenotype can exist, without amplification of the CCG repeat or cytogenetic expression of the fragile X, and that fragile X syndrome is a genetically homogeneous disorder involving FMR1. We also found random X-inactivation in the mother of the patient who was shown to be a carrier of this deletion.

The role of the RAS pathway in iAMP21-ALL.

Intrachromosomal amplification of chromosome 21 (iAMP21) identifies a high-risk subtype of acute lymphoblastic leukaemia (ALL), requiring intensive treatment to reduce their relapse risk. Improved understanding of the genomic landscape of iAMP21-ALL will ascertain whether these patients may benefit from targeted therapy. We performed whole-exome sequencing of eight iAMP21-ALL samples. The mutation rate was dramatically disparate between cases (average 24.9, range 5-51) and a large number of novel variants were identified, including frequent mutation of the RAS/MEK/ERK pathway. Targeted sequencing of a larger cohort revealed that 60% (25/42) of diagnostic iAMP21-ALL samples harboured 42 distinct RAS pathway mutations. High sequencing coverage demonstrated heterogeneity in the form of multiple RAS pathway mutations within the same sample and diverse variant allele frequencies (VAFs) (2-52%), similar to other subtypes of ALL. Constitutive RAS pathway activation was observed in iAMP21 samples that harboured mutations in the predominant clone (⩾35% VAF). Viable iAMP21 cells from primary xenografts showed reduced viability in response to the MEK1/2 inhibitor, selumetinib, in vitro. As clonal (⩾35% VAF) mutations were detected in 26% (11/42) of iAMP21-ALL, this evidence of response to RAS pathway inhibitors may offer the possibility to introduce targeted therapy to improve therapeutic efficacy in these high-risk patients.

A model of wound healing in chronically radiation-damaged rat skin.

The aim of this investigation was to develop a model for studying the chronic effects of radiation on wound healing in the rat. Six months after rats received a single radiation exposure of 20 Gy, a random-pattern dorsal skin flap was elevated. Two weeks after the flap was elevated, irradiated animals showed diminished scar formation and wound breaking strength, as compared with controls (P < 0.05). The effect of hyperbaric oxygen treatment was investigated in some rats who received 20 sessions at 2.4 atmospheres absolute for 90 min daily, 5 days per week, prior to flap elevation and 10 sessions after creation of the flap. Treated animals showed a trend toward improvements in wound breaking strength and scar formation (P = 0.06). A reproducible model of chronic radiation damage in the rat was established. Further studies involving investigations at times more that 2 weeks post-wounding are needed.

The fragile X syndrome II: preliminary data on growth and development in males.

Growth data--stature, body weight, occipito-frontal circumference (OFC), ear length and mean testicular volume (MTV)--in 61 males with the fragile X syndrome are presented. Small increases in the mean OFC and ear length and large increases in the MTV were found. The overgrowth of the head was evident in childhood. The characteristic facial appearance was deemed to be present in 60% of the subjects and was recognizable in childhood. Macro-orchidism (MTV of greater than or equal to 30 ml) was present in 80% of the adults but none of the children. Five subjects had a cleft palate, 11 serious eye disorders (3 with congenital nystagmus), and 4 had torticollis and/or kyphosis. Limited information on development suggested that mental retardation was present from early life and was not progressive. Although 3 subjects were autistic (2 with self abuse) most were pleasant, even tempered and cooperative men and boys.

Rett syndrome in monozygotic twins.

The evolution of the Rett syndrome in 29-year-old twin girls is presented. Evidence for monozygosity is given together with a brief account of the problems these girls posed to their family in early childhood.

Mild growth retardation and developmental delay, microcephaly, and a distinctive facial appearance.

We describe a brother and sister from one family and a girl from a second, unrelated family; they have a syndrome of pre- and post-natal growth deficiency, developmental delay, a friendly personality, microcephaly, and a distinctive facial appearance marked by thick eyebrows, full cheeks, and a short nose with the columella inserted below the nasal alae. We think this is a new syndrome probably inherited as an autosomal recessive trait.

Female relatives in families with the fragile X syndrome.

Three problems--mental retardation, having retarded children, and fear of having retarded children--are described in women in families with the fragile X syndrome. The investigation of one family with a counselling dilemma is presented in detail.

X-linked mental retardation with dystonic movements of the hands (PRTS): revisited.

A family with a syndrome of mental retardation, dystonic movements of the hands, and dysarthria (MIM no. 309510) was described and mapped to Xp22 by Partington et al. (Am J Med Genet 1988; 30:251-262). The original localization encompassed the distal half of the short arm of the X chromosome, with a peak lod score of 2.1 at the DXS41 locus. The gene localization for this disorder (PRTS) has now been refined using recently characterized dinucleotide repeat markers. The PRTS gene maps between DXS365 and DXS28, an interval estimated to be less than 15 cM. A peak lod score of 3.01 at a recombination fraction of zero was generated by 2-point linkage analysis with the marker DXS989. Dystonic movements may be progressive and could be overlooked in children. Clinical assessments of affected men who are mentally retarded should be critically evaluated for this manifestation, where they belong to families in which the gene localization overlaps with PRTS.

X-linked cutaneous amyloidosis: further clinical and pathological observations.

A 10-year follow-up of a family with X-linked cutaneous amyloidosis confirmed no more than streaks or spots of brown pigmentation of the skin in females but much more varied and severe manifestations in males. These included neonatal colitis, infantile diarrhea, recurrent respiratory infections, corneal dystrophy, photophobia, unruly hair with a frontal upsweep, dry skin, and mottled, muddy-brown pigmentation seen first on the inner thighs and spreading diffusely to the buttocks, trunk, and arms. Amyloid was found in the pigmented skin of adults of both sexes but not in children. An autopsy of a 50-year-old man, subject to recurrent pneumonia, confirmed the presence of amyloid in the skin, but it was not found in other organs. Changes in the lungs were those of late-stage diffuse pulmonary fibrosis. The pattern of inheritance is X-linked, but the pathogenesis remains obscure.

Fragile (X) expression, age and the degree of intellectual handicap in the male.

The proportion of cells expressing the fra(X) was compared to the guardian's opinion of who was the "brighter" in 31 sibships of 2 or more affected males. Six fra(X) positive males in the normal workforce were compared in a similar way to other affected relatives. A correlation was found between lower values of expression and "brightness" by the Wilcoxson signed rank test (less than 0.01, 2-tail). A decline in fra(X) expression occurs with age. Some apparently normal non-expressing transmitting males may be accounted for by these findings.

The fragile X syndrome I: familial variation in the proportion of lymphocytes with the fragile site in males.

A review of 61 males with the fragile X positive form of the Martin Bell syndrome from 30 families seen in the past 4 years suggests that the number of lymphocytes with the fragile site on the X chromosome (fra(X) ) in retarded males tends to be characteristic for the individual and similar to that found in other retarded males in the same family. The number of lymphocytes with fra(X) was not correlated with height, weight, occipitofrontal circumference, ear length or mean testicular volume in adults nor with age over the whole series.

Clinical screening score for the fragile X (Martin-Bell) syndrome.

A clinical score based on the manifestations of the fragile(X) syndrome has been formulated and applied to all individuals included in a fragile(X) case finding program in New South Wales. The total score can vary from 0 to 10. Individuals are scored 0, 1, or 2 in each of 5 categories considered indicative of the fragile(X) phenotype: family history of intellectual handicap, face length, ear configuration, personality, and body habitus. In a study of 1,206 individuals where the clinical scores were prospective (i.e., they had been given before the cytogenetic results were known) the percentage of those with the fragile(X) increased from 0.6% of those with scores of 4 or less to 14.6% with scores 5-7 and to 67% of those with scores 8-10. We have found the score simple to use in the circumstances where screening takes place (sheltered workshops and schools) and have reduced the number of individuals tested cytogenetically by 45%.

Fragile-X syndrome III: dermatoglyphic studies in males.

Dermatoglyphics of 39 males with the fragile-X syndrome were compared with those of 3 groups of control subjects; 497 school boys, 15 males with non-specific mental retardation, and 15 with Down syndrome. Compared with the control males, there was an increased frequency of radial loops, whorls, and arches on the fingers and of third interdigital patterns and abnormal creases on the hands, and a decreased frequency of ulnar loops and fourth interdigital patterns in the patients with the fragile-X syndrome. The mean a-b ridge count was lower than in controls and there were more patients than controls with an a-b ridge count less than 70. All of these differences were significant at p less than 0.01. There was no differences between patients and controls with respect to total ridge count on the fingers and the dermatoglyphics in other areas of the hands or feet. From this small study a preliminary index was developed that attempts to distinguish male patients with the fragile-X syndrome from normal male controls and males with non-fragile-X forms of mental retardation. The patterns on the left and right third fingers, the a-b ridge count, and the palmar creases were used in the index. Sixty-four % of patients with the fragile-X syndrome would be selected out if greater than or equal to + 0.5 was used as the criterion and 90% of these males would be expected to have the fragile-X chromosome.

Genes on the X chromosome are important in undiagnosed mental retardation.

The clinical genetic diagnosis was reviewed in 429 subjects with intellectual disability in the Australian Child and Adolescent Development (ACAD) study of behavioural problems. With minor differences, the overall "general distribution by causation" was similar to that to that found by the Consensus Conference of the American College of Medical Genetics in 1995. There was a significant male excess in the whole series which was shown to reside in those with "autism," those with undiagnosed nonsyndromic mental retardation (NSMR) and those with X-linked monogenic disorders. It is argued that a substantial proportion of undiagnosed NSMR is caused by genes on the X chromosome. Some of the practical problems of assigning individuals to diagnostic groups are discussed.

Is there a fragile(X) negative Martin-Bell syndrome?

During the course of the preventative screening program for the fra(X) syndrome, we identified 32 men with the phenotype but who were fra(X) negative. These were reviewed and none fitted the full criteria, so we were unable to confirm the existence of the fra(X) negative Martin-Bell syndrome. The literature and 4 families previously thought to have the fra(X) negative Martin-Bell syndrome were also reviewed. We were unable to make a concrete diagnosis of the fra(X) negative Martin-Bell syndrome.

Mortality in the fragile X syndrome: preliminary data.

Mortality was studied among 348 males and 433 females who had or who carried the gene for the fragile X syndrome. The average age of death was about 12 years lower than in the general population for both men and women but this was likely a bias of ascertainment. The commonest causes of death were cardiovascular, cerebrovascular and malignant disease similar to those in the general population. No evidence for any specific disease susceptibility was found in this preliminary study.

Confirmation of early menopause in fragile X carriers.

Fragile X carriers have a median age of menopause 6 to 8 years earlier than women in the general population, with 28% experiencing premature ovarian failure defined as menopause before the age of 40 years. This information was obtained from 203 returned questionnaires from women in the UK Fragile X Society.

Regional localisation of two non-specific X-linked mental retardation genes (MRX30 and MRX31).

Two genes responsible for X-linked mental retardation have been localised by linkage analysis. MRX30 maps to a 28 cM region flanked by the loci DXS990 (Xq21.3) and DXS424 (Xq24). A significant multipoint lod score of 2.78 was detected between the loci DXS1120 and DXS456. MRX31 maps to a 12 cM region that spans the centromere from DXS1126 (Xp11.23) to DXS1124 (Xq13.3). Significant two-point lod scores, at a recombination fraction of zero, were obtained with the loci DXS991 (Zmax = 2.06), AR (Zmax = 3.44), PGK1P1 (Zmax = 2.06) and DXS453 (Zmax = 3.31). The MRX30 localisation overlaps that of MRX8, 13, 20 and 26 and defines the position of a new MRX gene on the basis of a set of non-overlapping regional localisations. The MRX31 localisation overlaps the localisations of many of the pericentromeric MRX loci (MRX 1, 4, 5, 7, 8, 9, 12, 13, 14, 15, 17, 20, 22 and 26). There are now at least 8 distinct loci associated with non-specific mental retardation on the X chromosome defined, in order from pter to qter, by localisation for MRX24, MRX2, MRX10, MRX1, MRX30, MRX27, FRAXE and MRX3.