Biomedical subjects

N Akshoomoff

Publications and source records attributed to N Akshoomoff.

3 recordsLinked to original sources

PubMed2002

Transmission disequilibrium mapping at the serotonin transporter gene (SLC6A4) region in autistic disorder.

The serotonin transporter gene (SLC6A4, MIM 182138) is a candidate gene in autistic disorder based on neurochemical, neuroendocrine studies and the efficacy of potent serotonin transporter inhibitors in reducing ritualistic behaviors and related aggression. An insertion/deletion polymorphism (5-HTTLPR) in the promoter region and a variable number of tandem repeat polymorphism (VNTR) in the second intron, were previously identified and suggested to modulate transcription. Six previous family-based association studies of SLC6A4 in autistic disorder have been conducted, with four studies showing nominally significant transmission disequilibrium and two studies with no evidence of nominally significant transmission disequilibrium. In the present study, TDT was conducted in 81 new trios. A previous finding of transmission disequilibrium between a haplotype consisting of the 5-HTTLPR and intron 2 VNTR was replicated in this study, but not preferential transmission of 5-HTTLPR as an independent marker. Because of inconsistent transmission of 5-HTTLPR across studies, SLC6A4 and its flanking regions were sequenced in 10 probands, followed by typing of 20 single nucleotide polymorphisms (SNPs) and seven simple sequence repeat (SSR) polymorphisms in 115 autism trios. When individual markers were analyzed by TDT, seven SNP markers and four SSR markers (six SNPs, 5-HTTLPR and the second intron VNTR from promoter 1A through intron 2 of SLC6A4, one SSR from intron 7 of SLC6A4, one SNP from the bleomycin hydrolase gene (BLMH, MIM 602403) and one SSR telomeric to BLMH) showed nominally significant evidence of transmission disequilibrium. Four markers showed stronger evidence of transmission disequilibrium (TDT(max) P = 0.0005) than 5-HTTLPR.

Autistic Disorder↗

PubMed1989

Brainstem and middle latency auditory evoked potentials in autism and developmental language disorder.

Brainstem auditory evoked potentials (BAEP) and middle latency responses (MLR) were studied in 8 nonretarded subjects with infantile autism (mean age = 23.3, SD = 2.8), 8 subjects with receptive developmental language disorder (mean age = 16.3, SD = 1.4), and normal control subjects matched to each group for age, gender, and Performance IQ. Click stimuli were delivered monaurally to the left and the right ear and binaurally for both the BAEPs (70-dB HL, 7/sec) and the MLRs (60-dB HL, 13/sec). Amplitudes and latencies (Waves I to VI), interwave latencies (III-V, I-V, and I-III), and Wave I/V amplitude ratio of the BAEPs were determined for each group. For the MLR study, Wave Na, Pa, and Nb latencies, and Wave Na-Pa and Pa-Nb amplitudes were calculated. There were no consistent differences in the BAEP and MLR characteristics of the control and the experimental groups. These results suggest that the abnormal cognitive processes indexed by the cognitive and attention-related event-related potential components in infantile autism and receptive developmental language disorder are not due to abnormal sensory processing in the brainstem and in areas central to the brainstem whose activity generates the BAEPs and MLRs.

Adolescent↗

PubMed1989

Brainstem auditory evoked potentials in receptive developmental language disorder.

It has been hypothesized that receptive developmental language disorder (RDLD) may be explained by an auditory processing deficit. The neuroanatomical locus of this deficit is unknown. Brainstem auditory evoked potentials (BAEPs) reflect the functioning of the auditory nerve and auditory brainstem pathways to high-frequency acoustical stimulation in humans and reflect the first stages of auditory processing. These were studied in 12 subjects with RDLD (four females and eight males, ages 12 to 19) and twelve control subjects (three females and nine males, ages 14 to 24). Click intensity and rate of stimulation were varied. The BAEPs for the RDLD group were comparable to the control group as well as to hospital norms across intensity levels and stimulation rates. The evidence obtained suggests that a disorder in the neurophysiological systems underlying the BAEPs and reflecting initial stages of auditory processing is not essential for RDLD.

Adolescent↗