Alma Maciulis

Strong association of the third hypervariable region of HLA-DRβ1 with autism

We reported that the major histocompatibility complex (MHC) including the null allele of the C4B gene and the extended haplotype B44-C30-DR4 is associated with autism. We report now that the third hypervariable region (HVR-3) of certain DR β l alleles have very strong association with autism. The HVR-3 of DRβ1∗ 0401 or the shared HVR-3 alleles DR01∗ 0404 and DRβ1∗ 0101, was expressed on extended haplotypes in 23 of 50 (46%) autistic subjects as compared to only 6 of 79 (7.5%) normal subjects. Another HVR-3 sequence, the DRβ1∗ 0701 allele, was carried on extended haplotypes in 16 (32.0%) of the autistic subjects as compared to 8 (10.1 %) of the normal subjects.

The transmission disequilibrium test suggests that HLA-DR4 and DR13 are linked to autism spectrum disorder.

We have evaluated possible contributions of HLA-DRB1 alleles to autism spectrum disorder (ASD) in 103 families of Caucasian descent. The DR4 allele occurred more often in probands than controls (0.007), whereas the DR13,14 alleles occurred less often in probands than controls (p = 0.003). The transmission disequilibrium test (TDT) indicated that the ASD probands inherited the DR4 allele more frequently than expected (p = 0.026) from the fathers. The TDT also revealed that fewer DR13 alleles than expected were inherited from the mother by ASD probands (p = 0.006). We conclude that the TDT results suggest that DR4 and DR13 are linked to ASD. Reasons for the parental inheritance of specific alleles are poorly understood but coincide with current genetic research noting possible parent-of-origin effects in autism.

Increased frequency of the extended or ancestral haplotype B44-SC30-DR4 in autism

Autism likely results from several different etiologies or a combination of pathological mechanisms. Recent studies suggest that this disorder may be associated with immune abnormalities, pathogen-autoimmune processes and perhaps the major histocompatibility complex (MHC). In a preliminary study we found that 22 autistic subjects had an increased frequency of the extended or ancestral MHC haplotype B44-SC30-DR4. The current study attempted to confirm this observation by studying 23 additional randomly chosen autistic subjects, most of their parents and 64 unrelated normal subjects. In agreement with earlier findings B44-SC30-DR4 was associated with autism. In combining the data from the original and current studies, B44-SC30-DR4 or a substantial fragment of this extended haplotype was represented in 40% of the autistic subjects and/or their mothers as compared to about 2% of the unrelated subjects. It is concluded that one or more genes of the MHC is (are) involved in the development of some cases of autism.

Localization of the locus causing Spider Lamb Syndrome to the distal end of ovine Chromosome 6

Abstract. Spider Lamb Syndrome (SLS) is a semi-lethal congenital disorder, causing severe skeletal abnormalities in sheep. The syndrome has now been disseminated into several sheep breeds in the United States, Canada, and Australia. The mode of inheritance for SLS is autosomal recessive, making the identification and culling of carrier animals difficult due to their normal phenotype. Two large pedigrees segregating for the SLS mutation were established, and a genome scan with genetic markers from previously published genome maps of cattle and sheep was used to map the locus causing SLS. Genetic linkage between SLS and several microsatellite markers, OarJMP8, McM214, OarJMP12, and BL1038, was detected, thereby mapping the SLS locus to the telomeric end of ovine Chromosome (Chr) 6. Alignment of ovine Chr 6 with its evolutionary ortholog, human Chr 4, revealed a positional candidate gene, fibroblast growth factor receptor 3 (FGFR3).

Association of genes within the major histocompatibility complex with attention deficit hyperactivity disorder.

The objective was to determine whether a relationship exists among the complement C4B gene, a DR region gene and attention deficit hyperactivity disorder (ADHD). Thirty-one subjects with ADHD, their mothers, all but 5 of their fathers, and 90 normal subjects living in northern Utah were studied. DR and C4B typing were performed by serologic HLA typing techniques and the DNA methods PCR-RFLP. The alleles of 2 genes, the null allele of the C4B gene and the beta 1 allele of the DR gene, encode for products involved in immune function and regulation. Each of these alleles was found to be significantly associated with ADHD. Moreover, approximately 55% of the ADHD subjects carried both of these alleles on 1 of their chromosomes, compared to only 8% of normal controls. Genes related to the immune system may be associated with development of the symptoms of ADHD.

Decreased Expression of CD95 (FAS/APO-1) on CD4+ T-lymphocytes from Participants with Autism

Although autism remains an enigmatic disease, there is mounting evidence that the immune system plays an important role in the pathogenesis. Immune system involvement is apparently widespread as numerous humoral and cellular abnormalities have been reported in both the innate and adaptive responses. Fas (CD95/APO-1) is a type I cell-surface protein from the TNF/NGF-R superfamily present on the surface of many immune related cells. Fas activation is instrumental in starting a complicated chain of events that results in programmed cell death (apoptosis) by DNA fragmentation. Preliminary data is presented, which indicate that subjects with austism have lower levels of Fas on their CD4+ helper T cells (p = .048) than have normal subjects. Data also indicates subjects with autism have significantly higher levels of soluble Fas (p = .01) than have normal subjects. A maturing individual must eliminate cells for proper morphogenesis to occur. Preliminary data suggest that faulty apoptosis may be involved in the pathogenesis of autism.

Preventing experimental vertical transmission of scrapie by embryo transfer

This study investigated whether the transmission of naturally occurring scrapie in sheep can be prevented using embryo transfer. Embryos were collected from 38 donor ewes in a Suffolk sheep flock with a high incidence of naturally occurring scrapie, treated with a sanitary procedure (embryo washing) recommended by the International Embryo Transfer Society and then transferred to 58 scrapie-free recipient ewes. Ninety-four offspring were produced. None of the offspring or the recipient ewes developed scrapie. Furthermore, offspring derived from embryos collected from donor ewes bred to the immunohistochemically positive ram did not develop scrapie. We conclude that scrapie was not transmitted to offspring via the embryo nor was the infective agent transmitted to recipient ewes during embryo transfer procedures.

Is Decreased Blood Plasma Concentration of the Complement C4B Protein Associated with Attention-Deficit Hyperactivity Disorder?

OBJECTIVE The complement system is a group of blood proteins that play an important role in defending against viral and bacterial infections. The objective of this investigation was to study the plasma levels of the C4B protein in attention-deficit hyperactivity disorder (ADHD) in an attempt to associate infections with the development of some cases of this disorder. METHOD C4B plasma protein levels were studied using an enzyme-linked immunosorbent assay in a group of 23 subjects meeting DSM-III-R criteria for ADHD and a similar number of age- and sex-matched controls. Also studied were parents of the ADHD subjects. RESULTS C4B plasma levels (157.0 micrograms/mL) in the ADHD subjects were significantly (p < .01) lower than those (239.3 micrograms/mL) in the normal age-matched subjects. Mothers of the ADHD subjects also had significantly lower C4B values compared with mothers of normal children. On the other hand, C4B values in the fathers were not significantly altered. CONCLUSIONS Decreased C4B levels in ADHD, if replicated, may represent an important marker for ADHD (or a subgroup of ADHD). It also seems plausible that C4B levels are an important etiological factor for ADHD.

Polymorphic distribution of the ovine prion protein (PrP) gene in scrapie-infected sheep flocks in which embryo transfer was used to circumvent the transmissions of scrapie.

The genetic sequence of the ovine prion protein (PrP) gene between codons 102 and 175 with emphasis on ovine PrP gene codons 136 and 171 was determined, and the polymorphic distribution of the ovine PrP gene in the scrapie-exposed Suffolk embryo donors and offspring from these donors that were transferred to scrapie-free recipient ewes was investigated in this study. The most common genotype was AA(136)QQ(171) (70% and 63% in the donor and offspring flocks, respectively), which is considered a high risk genotype in US Suffolk sheep. Although embryos were collected from scrapie-positive donors and many embryos had the high risk genotype, no scrapie occurred in the resulting offspring. Based upon the results of this study, we conclude that vertical transmission of scrapie can be circumvented using embryo transfer procedures even when the offspring have the high risk genotype.

True hermaphroditism in a wild sheep: A clinical report.

Intersexuality in sheep is rare, with the freemartin anomaly being the most common. We describe here a true hermaphrodite in a wild sheep. An F(1) wild sheep ewe of Argali-mouflon X Mexican desert bighorn breeding was bred to an F(1) ram of the same breeding. A single lamb was born with the external appearance of a normal female. The lamb grew faster than its female cohorts, and by 6 months of age exhibited the aggressive behavior, size, coloration and horn development associated with males. Phenotypically, the intersex had female external genitalia with an enlarged clitoris. A human chorionic gonadotrophin (hCG) response test was performed when the intersex was 1-year-old and serum testosterone, progesterone and estradiol levels were compared to the response of a normal female and male of similar age and breeding. An exploratory celiotomy revealed two gonadal-like structures associated with a female reproductive tract. Histopathology of the structures revealed spermatogenically inactive testicular vessels and ovarian tissue with primary follicles. The reproductive tract was complete with two uterine horns and a cervix. The intersexuality is attributed to an XX/XXY mosaic.