C to T nucleotide substitution in codon 713 of amyloid precursor protein gene not found in 86 unrelated schizophrenics from multiplex families.

Jones et al. Nature Genet 1:306-309, [1992] recently detected a C to T nucleotide transition (codon 713) in a highly conserved region of the beta-amyloid precursor gene in a single case of schizophrenia. Although the sequence variant may be a natural polymorphism, it is crucial to determine whether the mutation might be present in a small subset of schizophrenics. We isolated DNA from 86 unrelated chronic schizophrenics who had a first degree relative with chronic schizophrenia or chronic schizoaffective disorder. After PCR amplification of exon 17, we were unable to detect the presence of the codon 713 variant in these schizophrenic cases, as well as in 156 controls. Unless additional cases are found with the codon 713 mutation, it is unlikely that the sequence variant is pathogenic for schizophrenia.

Familial thyroid disease and delayed language development in first admission patients with schizophrenia.

One hundred consecutive first admission patients with a DSM-III-R diagnosis of schizophrenia, schizoaffective disorder, or schizophreniform disorder were compared with 100 randomly selected community controls. Childhood histories of physical, medical, and perinatal trauma, as well as physical and cognitive development, were examined by structured interviews with all available mothers of patients and controls. The prevalence of specific psychiatric disorders and several medical illnesses among first degree and more distant relatives was determined by family history questionnaires. The patient group did not have an excess of childhood head injuries, serious infections, or perinatal/birth complications compared with controls. With social class level taken into account, it was found that the acquisition of reading skills occurred significantly later in patients than controls. Family histories of schizophrenia and thyroid disorders were significantly more frequent among patients than controls. These data fail to indicate any childhood physical or medical environmental trauma that could lead to an increased risk for schizophrenia, although patients were substance abusers to a greater extent than controls. This study also confirms the already known contribution of familial factors and suggests an association of the inheritance of thyroid disorders with schizophrenia. Delayed development of reading skills suggests that precursers of illness may appear early in life before psychosis is evident.

Intestinal uptake of fluorescent microspheres in young and aged mice.

Rhodamine B-labeled synthetic latex particles (microspheres), 1.8 micron in diameter, were administered by gavage 5 days per week to young (24 days) and aged (18 months) mice. After 25 days (19 gavages), the particles were assayed in solubilized tissues by depositing them on filters and counting under fluorescence microscopy. Aged mice exhibited significantly more fluorescent particle accumulation in Peyer's patches but significantly less in lungs than young mice. Mesenteric lymph nodes and Peyer's patch-free intestinal segments contained measurable latex, but differences between young and aged animals were not significant. Liver contained only trace amounts of latex, and spleen and kidney were latex free in both young and aged animals. Nonquantitative observations on KOH-glycerol-cleared whole Peyer's patches and slices of liver, lung, and mesenteric lymph node were similar.