Phenotypic spectrum associated with PTCHD1 deletions and truncating mutations includes intellectual disability and autism spectrum disorder.

Studies of genomic copy number variants (CNVs) have identified genes associated with autism spectrum disorder (ASD) and intellectual disability (ID) such as NRXN1, SHANK2, SHANK3 and PTCHD1. Deletions have been reported in PTCHD1 however there has been little information available regarding the clinical presentation of these individuals. Herein we present 23 individuals with PTCHD1 deletions or truncating mutations with detailed phenotypic descriptions. The results suggest that individuals with disruption of the PTCHD1 coding region may have subtle dysmorphic features including a long face, prominent forehead, puffy eyelids and a thin upper lip. They do not have a consistent pattern of associated congenital anomalies or growth abnormalities. They have mild to moderate global developmental delay, variable degrees of ID, and many have prominent behavioral issues. Over 40% of subjects have ASD or ASD-like behaviors. The only consistent neurological findings in our cohort are orofacial hypotonia and mild motor incoordination. Our findings suggest that hemizygous PTCHD1 loss of function causes an X-linked neurodevelopmental disorder with a strong propensity to autistic behaviors. Detailed neuropsychological studies are required to better define the cognitive and behavioral phenotype.

Subacute sclerosing panencephalitis in the differential diagnosis of encephalitis.

The authors describe five cases of subacute sclerosing panencephalitis (SSPE) identified through the California Encephalitis Project that emphasize the importance of considering SSPE in the differential diagnosis of encephalitis, particularly among pediatric patients. SSPE was not suspected in the differential diagnosis of three of the cases until results of measles testing were known. The diagnosis of SSPE is often not considered by clinicians because of its rarity in the United States and the nonspecific clinical manifestations at onset.

Differential diagnosis and treatment of conversion disorder and Guillain-Barre syndrome.

Three cases are presented which illustrate the possible difficulties in differentiating between the diagnoses of Guillain-Barre Syndrome and conversion disorder. Accepted criteria are specified for each condition, as well as some associated features often characteristic of similar cases. Supportive interdisciplinary treatment for Guillain-Barre Syndrome is reviewed, and an interdisciplinary multi-modal approach to treatment of conversion disorder is described.

The effect of valproic acid on plasma carnitine levels.

Plasma total, free, and acyl carnitine levels were determined in four groups of children: (1) those treated with valproic acid as monotherapy (n = 43), (2) those treated with valproic acid plus other antiepileptics as polytherapy (n = 91), (3) those treated with other antiepileptic drugs alone (n = 43), and (4) normal patients (n = 89). The mean free carnitine level was significantly lower in both the valproic acid monotherapy (29.9 mumol/L) and polytherapy (21.4 mumol/L) groups compared with normal subjects (36.8 mumol/L); it was also significantly lower than that in patients treated with other antiepileptic drugs (36.7 mumol/L). Comparison of valproic acid polytherapy and monotherapy yielded significantly lower free carnitine levels in the polytherapy group. The ratios of acyl to free carnitine for monotherapy (0.41) and polytherapy (0.45) were significantly higher than that in the normal group (0.25). This study indicates that a general decrease in the carnitine pool should be anticipated in patients taking valproic acid polytherapy and, to a lesser degree, monotherapy. Carnitine levels in the group taking other drugs did not differ from normal.

ATFresno: a phenotype linking ataxia-telangiectasia with the Nijmegen breakage syndrome.

This report describes twin girls with typical features of ataxia-telangiectasia, including increased alpha-fetoprotein, radio-resistant DNA synthesis, characteristic chromosome abnormality, and immunodeficiency. They have, in addition, microcephaly and mental retardation. Complementation studies were performed utilizing Sendai virus--mediated fusion of fibroblast cell lines. Complementation was observed with patients in ataxia-telangiectasia complementation groups A, C, and E but not with the cell line from a patient with the Nijmegen breakage syndrome, in which patients have microcephaly, radio-resistant DNA synthesis, chromosome aberrations, and immunodeficiency but lack ataxia and telangiectasia. These data suggest that the Nijmegen breakage syndrome and the patients described here are not genetically distinct entities but form a spectrum of one disorder.

High-affinity transport of glutamate in rat brain microvessels.

The maintenance of low extracellular concentrations of glutamate in the brain is a complex process in which the role of capillary transport is poorly understood. We examined the kinetics and substrate specificity of glutamate uptake by isolated rat brain microvessels. We showed that these microvessels take up glutamate by an energy- and temperature-dependent, concentrative, high-affinity active transport system with Km of about 2 microM. The presence of this active transport system, coupled with the known slow inward transport of glutamate across the blood-brain barrier, allows us to suggest that this capillary transport system may function in vivo in the unidirectional outward transport of glutamate from brain to blood.

Ocular, cerebral and cutaneous malformations: confirmation of an association.

A newborn with multiple congenital abnormalities including an orbital cyst, cerebral cysts, skin tags and focal dermal defects is described. This case is similar to two patients reported by Delleman & Oorthuys in 1981 under the designation "Oculo-cerebro-cutaneous syndrome." Features common to other syndromes are discussed and additional cases with some similarities are also presented. The occurrence of this process in a new population and the cited variability helps confirm and define this association.

Pyruvate carboxylase activity in subacute necrotizing encephalopathy (Leigh's disease).

Leigh's disease is a heterogeneous group of disorders, in which clinical and biochemical features suggest abnormal pyruvate metabolism. In two patients with Leigh's disease, diagnosed according to rigorous clinical, radiographic, and histologic criteria, we tested the hypothesis that pyruvate carboxylase deficiency might be the primary etiology. Pyruvate carboxylase specific activities in extracts of cultured skin fibroblasts from both patients were in the normal range. These results, together with other evidence, suggest that isolated pyruvate carboxylase deficiency does not cause the Leigh's disease phenotype.

Endothelial growth factor present in tissue culture of CNS tumors.

Human endothelial cells obtained from postpartum umbilical veins and placed in primary tissue cultures were treated with media from cultures of human and experimental central nervous system tumors. Endothelial proliferation was determined by the uptake of 3H thymidine with autoradiography and represented as the thymidine labeling index (TI), which is the proportion of 3H thymidine-labeled endothelial cells to total number of cells counted. There was a marked increase in the TI when tumor-conditioned medium was added to endothelial cultures (range 28.7% to 98.3%) when compared to controls (2.1%) and endothelium with conditioned media from fibroblasts (4.5%). This study demonstrates the presence of a chemical substance produced by tumor cells which results in endothelial proliferation. The system described provides a useful assay technique for the further characterization of this endothelial growth factor.

Uptake of neurotransmitters and precursors by clonal lines of astrocytoma and neuroblastoma: III. Transport of choline.

Clonal lines of glial, neuronal, and nonneural origin accumulate choline via a high-affinity carrier-mediated transport system withK m in the range of 10-14 µM. These cell lines also accumulate choline by a second system that is not saturable at 10 mM choline, and that may represent diffusion. The transport of choline in glial cells differs from that seen in neuronal cells with respect to its Na(+) requirement. The omission of Na(+) from the incubation medium reduces high-affinity choline transport in neuronal cells and enhances it in glial cells. Kinetic analysis of the data indicates that reversible cholinesterase inhibitors and hemicholinium-3 (HC-3) inhibit the high-affinity transport system for choline. On the other hand, the diffusional or low-affinity component of choline transport in either cell type appears to have no Na(+) requirement and is unaffected by either cholinesterase inhibitors or 10(-4) M HC-3. The neuronal-glial differences in the Na(+) requirement of choline transport may be related to the coupling of transport to choline metabolism, which differs in the two cell types. The presence of a high-affinity transport system for choline in clonal glial lines used as models of normal glia suggest that glia may modulate the availability of choline for acetylcholine synthesis at cholinergic synapses.

In vitro demonstration of an endothelial proliferative factor produced by neural cell lines.

Cultured endothelial cells exhibit a six- to tenfold increase in thymidine labeling index in response to a soluble factor elaborated by clonal cell lines of neural origin. This factor, endothelial proliferation factor, appears to be a unique property of tumor cells and may mediate the vascularization of these neoplasms.

Characterization of the terminal degradation products of canine fibrinogen by plasmin.

Fibrinogen, isolated from canine plasma by the successive procedures of (1) freezing and thawing, (2) fractional precipitation with 25% saturated (HN4)2SO4 and (3) Sepharose 6B gel-filtration, had a molecular weight of 282 000 by the rapid sedimentation equilibrium method. However, a molecular weight for canine fibrinogen of 332 000, which is closer to that reported for human and bovine fibrinogens (340 000 plus or minus 20 000), was obtained from the sum of the molecular weights of the Aalpha, Bbeta and gamma chains, determined from dodecylsulfate gel electrophoretic patterns of reduced fibrinogen. Canine fibrinogen, subjected to proteolysis by urokinase-activated plasminogen for 24 h, contained degradation fragments D and E which were isolated by starch block electrophoresis and Sephadex G-200 gel-filtration. The purified D and E fragments with sedimentation coefficients of 5.0 S and 2.5 S had weight average molecular weights of 89 000 and 42 000, respectively by the rapid sedimentation equilibrium method. The ratio of D to E was 2:1 per parent fibrinogen molecule. Antigenic analysis according to anti-fibrinogen antiserum showed that both D and E fragments were antigenically deficient to native fibrinogen and revealed a reaction of non-identity with each other. Upon immunoelectrophoresis at pH 8.2, D and E had different electrophoretic mobilities. Preliminary studies indicate that based on thrombin time alone, D has anticoagulant activity while E appears to be a coagulation potentiator. Canine fibrinogen apparently consist of two core fragments with dissimilar chemical characteristics in common with the fundamental structures of human and bovine fibrinogens.