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POMT2 mutation in a patient with 'MEB-like' phenotype.

Mutations in POMT2 have so far only been reported in patients with Walker-Warburg phenotype. We report heterozygous POMT2 mutations in an a girl with a milder phenotype characterized by mental retardation, microcephaly, hypertrophy of the quadriceps and calf muscles, and structural brain changes mostly affecting the posterior fossa. Our findings suggest that, as previously reported for POMT1 and FKRP, mutations in the POMT2 can also be associated with clinical heterogeneity.

Amino Acid Sequence↗

Deficiency of mitochondrial ATP synthase of nuclear genetic origin.

We present clinical and laboratory data from 14 cases with an isolated deficiency of the mitochondrial ATP synthase (7-30% of control) caused by nuclear genetic defects. A quantitative decrease of the ATP synthase complex was documented by Blue-Native electrophoresis and Western blotting and was supported by the diminished activity of oligomycin/aurovertin-sensitive ATP hydrolysis in fibroblasts (10 cases), muscle (6 of 7 cases), and liver (one case). All patients had neonatal onset and elevated plasma lactate levels. In 12 patients investigated 3-methyl-glutaconic aciduria was detected. Seven patients died, mostly within the first weeks of life and surviving patients showed psychomotor and various degrees of mental retardation. Eleven patients had hypertrophic cardiomyopathy; other clinical signs included hypotonia, hepatomegaly, facial dysmorphism and microcephaly. This phenotype markedly differs from the severe central nervous system changes of ATP synthase disorders caused by mitochondrial DNA mutations of the ATP6 gene presenting mostly as NARP and MILS.

Adenosine Triphosphate↗

Brains, islands and evolution: breaking all the rules.

The announcement in 2004 that a small-brained hominin, Homo floresiensis, had been discovered on the island of Flores, Indonesia, was hailed as a major scientific breakthrough because it challenged preconceptions about the evolution of our closest relatives. Now, just over two years later, questions raised by the interpretation of the fossil abound. In a series of recent papers, critics have questioned the interpretation of the small brain volume of the fossil as that of a new hominin species, suggesting instead that it was due to microcephaly. The arguments raised by critics and advocates alike prompt a re-examination of ideas about what is possible during the evolution of the brain.

Animals↗

Lymphocytic choriomeningitis virus: an underdiagnosed cause of congenital chorioretinitis.

PURPOSE: To elucidate the role and clinical spectrum of congenital lymphocytic choriomeningitis virus infection as a cause of chorioretinopathy, congenital hydrocephalus, and macrocephaly or microcephaly in the United States. METHODS: We performed complete ophthalmologic surveys of all residents at Misericordia, a home for the severely mentally retarded in Chicago, and prospectively evaluated all patients with chorioretinitis or chorioretinal scars during a 36-month period at Children's Memorial Hospital, also located in Chicago. Sera for patients demonstrating chorioretinal scars (a sign of intrauterine infection) were tested for Toxoplasma gondii, rubella virus, cytomegalovirus, and herpes simplex virus and lymphocytic choriomeningitis virus antibodies. RESULTS: Four of 95 patients examined at the home had chorioretinal scars, and two of these patients had normal T. gondii, rubella virus, cytomegalovirus, and herpes simplex virus titers and dramatically elevated titers for lymphocytic choriomeningitis virus. Three of 14 cases of chorioretinitis at the hospital had normal T. gondii, rubella virus, cytomegalovirus, and herpes sim-plex virus titers and elevated lymphocytic choriomeningitis virus antibody titers. (A fourth case, diagnosed in 1996, was reported 2 years ago.) CONCLUSIONS: Lymphocytic choriomeningitis virus was responsible for visual loss in two of four children secondary to chorioretinitis in a population of severely retarded children. The six new cases of lymphocytic choriomeningitis virus chorioretinitis identified in these two populations over the last 3 years, compared with the total number ever reported in the United States (10 cases), suggests that lymphocytic choriomeningitis virus may be a more common cause of congenital chorioretinitis than previously believed. Because its consequences for visual and psychomotor development are devastating, we conclude that the workup for congenital chorioretinitis should include lymphocytic choriomeningitis virus serology, especially if T. gondii, rubella virus, cytomegalovirus, and herpes simplex virus titers are negative.

Antibodies, Viral↗

A case of insertional translocation resulting in partial trisomy 16p.

This report concerns the case of a boy with partial trisomy 16p resulting from the insertional translocation of the short arm of chromosome 16 into the long arm of chromosome 1 in his father. He was referred for genetic testing because of mental retardation, short stature, microcephaly, seizures and multiple dysmorphic features. Chromosome analysis performed in the child demonstrated the presence of additional material in the long arm of chromosome 1. Paternal high resolution chromosome analysis and fluorescence in situ hybridisation revealed the following karyotype: 46,XY,ins(1;16)(q42;p13.1p13.3), while the karyotype of the boy is 46,XY,der(1),ins(1;16)(q42;p13.1p13.3)pat. This is the first reported case of partial trisomy 16p due to paternal insertional translocation.

Abnormalities, Multiple↗

Treatment of children with Down syndrome and growth retardation with recombinant human growth hormone.

The effect of recombinant human growth hormone on children with Down syndrome who had growth retardation and microcephaly was examined. Thirteen children with trisomy 21 without congenital heart disease who were short for age (-1.19 to -3.5 standard deviation score) and microcephalic (-1.58 to -6.60 standard deviation score) were given recombinant human growth hormone, 0.1 mg/kg subcutaneously, 3 days a week for 1 year. Before treatment, peak serum growth hormone concentrations were less than 10 micrograms/L after levodopa and clonidine stimulation tests in five patients, after clonidine in three patients, and after levodopa in three patients. Three patients had nocturnal integrated growth hormone concentrations of 0.5, 1.5 and 0.65 micrograms/L, respectively. The mean growth rate before treatment was 5.4 +/- 1.6 cm/yr and increased to 12.2 +/- 3.2 cm/yr (p less than 0.001) after 12 months of recombinant human growth hormone treatment. The mean head circumference standard deviation score before treatment was -3.1 +/- 1.3 and increased to -2.3 +/- 1.2 (p less than 0.001) at 12 months. Bone age before and 1 year after treatment increased in correspondence with chronologic age. Plasma hemoglobin A1c concentration was normal during treatment with recombinant human growth hormone. The mean plasma concentrations of insulin-like growth factor I at baseline and at 12 months were 0.54 +/- 0.19 U/ml and 1.25 +/- 0.97 U/ml, respectively (p less than 0.02). We conclude that recombinant human growth hormone therapy can result in a significant increase in annual growth rate and head circumference in children with Down syndrome, without significant side effects.

Age Determination by Skeleton↗

Fetal brain disruption sequence.

The fetal brain disruption sequence is a recognizable pattern of defects that includes moderate to profound microcephaly, overlapping sutures, occipital bone prominence, and scalp rugae. The condition is postulated to arise from partial brain disruption during the second or third trimester with subsequent fetal skull collapse resulting from decreased intracranial hydrostatic pressure. Proposed causes include prenatal viral or parasitic infections and vascular disruptions. We report seven infants with the fetal brain disruption sequence. Two of these patients died. A changing phenotype with time was seen in three. Recognition of this phenotype is critical because the condition has a uniformly poor prognosis for infants but the recurrence risk in future pregnancies is low.

Abnormalities, Multiple↗

The fetal trimethadione syndrome.

Three families are described in which each of the mothers took trimethadione during pregnancy. From a comparison of siblings in each family and of others exposed to trimethadione in utero, a specific phenotype is delineated. Features included in the fetal trimethadione syndrome are developmental delay, speech difficulty, V-shaped eyebrows, epicanthus, low-set ears with anteriorly folded helix, palatal anomaly, and irregular teeth. Additional anomalies in some of the patients include intrauterine growth retardation, short stature, microcephaly, cardiac anomaly, ocular anomaly, hypospadias, inguinal hernia, and simian creases.

Abnormalities, Drug-Induced↗

Choanal atresia and associated multiple anomalies.

Seventeen unrelated patients with multiple anomalies of unknown etiology were identified by the presence of choanal atresia. A regularly recurring pattern of associated features involving mental retardation, postnatal growth deficiency, hypogenitalism (males), small ears, cardiac defects, micrognathia, postnatal microcephaly, and ocular coloboma was identified. Choanal atresia when accompanied by multiple anomalies of unknown etiology has a serious prognosis with a predictable pattern of associated defects.

Abnormalities, Multiple↗

Chronic hypernatremia from a congenital defect in osmoregulation of thirst and vasopressin.

An infant with microcephaly and delayed development was found to have chronic asymptomatic hypernatremia. Computerized brain tomography disclosed dysplasia of the midline structures, septum pellucidum and corpus collosum. Evaluation revealed defective osmoregulation, hypothalamic hypothyroidism, and hypogonadotropinism. He showed no desire to drink at plasma osmolalities over 330 mOsm/kg. His plasma vasopressin levels (less than or equal to 1.4 pg/ml) were inappropriately low relative to his high levels of plasma osmolality (greater than or equal to 310 mOsm/kg), which might be accounted for by either deficient neurohypophyseal vasopressin stores or disturbance of the hypothalamic osmoreceptors governing vasopressin. The first possibility was ruled out by demonstrating normal vasopressin response (167 pg/ml) to nonosmotic (emetic) stimulation. Under baseline conditions, his urine was concentrated up to 747 mOsm/kg and urine volume was low. With water loading, maximal water diuresis developed (urine osmolality 68 mOsm/kg), but his plasma osmolality remained in the hyperosmolar range (312 mOsm/kg). Treatment with a vasopressin analogue, desamino-D-arginine vasopressin, and forced hydration restored plasma osmolality and plasma sodium to normal. These findings indicate a severe defect in the hypothalamic osmoreceptors controlling thirst and vasopressin secretion with normal vasopressin stores and preserved vasopressin responsiveness to nonosmotic stimuli. To our knowledge, this report provides the first documentation of selective osmoreceptor defect in conjunction with congenital dysplasia of midline brain structures.

Brain↗

Hypoplastic right-sided heart complex: a cluster of cases with associated congenital birth defects. A new syndrome?

Fourteen infants, all born within the same geographic area in a two-year period, had hypoplastic right-sided heart complex associated with a high incidence of other congenital defects. No common teratogenic exposure or genetic relationships were discovered. Twelve of the 14 infants were conceived in the spring or summer. Significant elevations in serum antibody titers against coxsackie group B virus and echoviruses were noted in the general referral population during those spring and summer quarters. Cardiac defects included a hypoplastic right ventricle in every case; three types were noted. Varying degrees of right-sided valvular lesions and other intracardiac defects accompanied the hypoplastic ventricle. Eleven infants had extracardiac congenital anomalies: 10 had microcephaly, two had micrognathia with posterior cleft palate, four had low-set ears, and one had arrhinencephaly. The high incidence of extracardiac defects in the syndrome (79%) is in distinct contrast to the incidence reported in the New England Regional Infant Cardiac Program in infants who had pulmonic atresia with intact ventricular septum.

Abnormalities, Multiple↗

Maternal hyperphenylalaninemia fetal effects.

Thirty-four children of 11 mothers with untreated hyperphenylalaninemia had a pattern of malformation consisting of prenatal and postnatal growth retardation, microcephaly and central nervous system dysfunction, increased incidence of malformations, and a peculiar facial appearance. Maternal hyperphenylalaninemia appears to be teratogenic, with a variability related to the blood phenylalanine concentration.

Adolescent↗

Toluene embryopathy.

Three children with microcephaly, central nervous system dysfunction, minor craniofacial and limb anomalies, and variable growth deficiency were born to women who inhaled large quantities of pure toluene throughout pregnancy. The features in our patients were reminiscent of the patterns of malformation previously described following in utero exposure to alcohol, certain anticonvulsants, and hyperphenylalaninemia. It is possible that there is a variable and nonspecific teratogenic phenotype characterized by alterations in growth, development, and morphogenesis. Careful evaluation and monitoring of infants exposed to toluene in utero are needed to determine the significance of our findings.

Abnormalities, Drug-Induced↗

Effects of prematurity and dysmaturity on growth at age 5 years.

Forty-two term and 106 preterm appropriate for gestational age (AGA), and 43 term and 31 preterm small for gestational age (SGA) children were observed from birth to age 5 years. Parents' weight and height were also measured in 193 subjects including 97 couples. The percentage of short children was higher in SGA (17%) than in AGA (3.4%) children (P less than 0.01). This difference was significant in the preterm but not in the term children, suggesting that early failure of growth in utero can result in reduced growth in children. The findings were similar for weight and head circumference, but microcephaly was more frequent in term SGA (30%) than in preterm SGA (6.4%) children (P less than 0.05), suggesting that late impaired growth in utero can result in poor growth of the head. Height at the age of 5 years correlated with the parents' height only in AGA children, and with length at birth in SGA children. Weight of the 5-year-old children correlated with the mother's weight only in AGA children. Multivariate analysis in 66 couples and their children confirmed a greater tendency toward the influence of parental factors in AGA children and a more significant relationship with perinatal factors in SGA children.

Birth Weight↗

Maternal phenylketonuria: magnetic resonance imaging of the brain in offspring.

Phenylketonuria (PKU) produces white matter changes identifiable by magnetic resonance imaging. These changes occur postnatally. Offspring of untreated mothers with PKU also have a brain effect, expressed as microcephaly and mental retardation. This effect occurs prenatally. To determine whether the white matter changes seen in PKU are also present in maternal PKU offspring, despite the different developmental stages of exposure to PKU, we performed brain magnetic resonance imaging studies in seven maternal PKU offspring, five from essentially untreated pregnancies and two from treated pregnancies. None had white matter changes, although the one offspring with PKU had delayed myelination. However, hypoplasia of the corpus callosum was present in three of the four offspring from untreated pregnancies and in the offspring from a maternal PKU pregnancy not treated until the third trimester. Unlike PKU, white matter changes are not a feature of the brain effect in maternal PKU. However, hypoplasia of the corpus callosum is a feature of maternal PKU and is probably a result of inhibition of corpus callosum development at 8 to 20 weeks of gestation. The hypoplastic corpus callosum could be a marker for brain effect in maternal PKU and may have implications for the cognitive deficits in these offspring.

Adolescent↗

Solitary pelvic kidney and neuroblastoma in a child.

We describe a case of a solitary pelvic kidney coexisting with adrenal and pelvic neuroblastoma in a child with multiple malformations, including microcephaly, hypertelorism, aortic coarctation and a bifid uterus. The association of a solitary kidney and neuroblastoma has not been reported previously.

Abnormalities, Multiple↗

Nibrin, a novel DNA double-strand break repair protein, is mutated in Nijmegen breakage syndrome.

Nijmegen breakage syndrome (NBS) is an autosomal recessive chromosomal instability syndrome characterized by microcephaly, growth retardation, immunodeficiency, and cancer predisposition. Cells from NBS patients are hypersensitive to ionizing radiation with cytogenetic features indistinguishable from ataxia telangiectasia. We describe the positional cloning of a gene encoding a novel protein, nibrin. It contains two modules found in cell cycle checkpoint proteins, a forkhead-associated domain adjacent to a breast cancer carboxy-terminal domain. A truncating 5 bp deletion was identified in the majority of NBS patients, carrying a conserved marker haplotype. Five further truncating mutations were identified in patients with other distinct haplotypes. The domains found in nibrin and the NBS phenotype suggest that this disorder is caused by defective responses to DNA double-strand breaks.

Amino Acid Sequence↗

Prenatal and early postnatal treatment in 3-phosphoglycerate-dehydrogenase deficiency.

3-phosphoglycerate-dehydrogenase (3-PGDH) deficiency is an L-serine biosynthesis disorder, characterised by congenital microcephaly, severe psychomotor retardation, and intractable seizures. We report prenatal diagnosis of an affected fetus by DNA mutation analysis. Ultrasound assessment showed a reduction in fetal head circumference from the 75th percentile at 20 weeks' gestation to the 29th percentile at 26 weeks. L-serine was then given to the mother, which resulted in an enlarged fetal head circumference to the 76th percentile at 31 weeks. At birth, the girl's head circumference was normal, and at 48 months' follow-up, her psychomotor development has been unremarkable. 3-PGDH deficiency is an inborn metabolic error that can be successfully treated antenatally.

Amino Acid Metabolism, Inborn Errors↗