Phenotypic characterization of individuals with 30-40 CAG repeats in the Huntington disease (HD) gene reveals HD cases with 36 repeats and apparently normal elderly individuals with 36-39 repeats

Abnormal CAG expansions in the IT-15 gene are associated with Huntington disease (HD). In the diagnostic setting it is necessary to define the limits of the CAG size ranges on normal and HD-associated chromosomes. Most large analyses that defined the limits of the normal and pathological size ranges employed PCR assays, which included the CAG repeats and a CCG repeat tract that was thought to be invariant. Many of these experiments found an overlap between the normal and disease size ranges. Subsequent findings that the CCG repeats vary by 8 trinucleotide lengths suggested that the limits of the normal and disease size ranges should be reevaluated with assays that exclude the CCG polymorphism. Since patients with between 30 and 40 repeats are rare, a consortium was assembled to collect such individuals. AU 178 samples were reanalyzed in Cambridge by using assays specific for the CAG repeats. We have optimized methods for reliable sizing of CAG repeats and show cases that demonstrate the dangers of using PCR assays that include both the CAG and CCG polymorphisms. Seven HD patients had 36 repeats, which confirms that this allele is associated with disease. Individuals without apparent symptoms or signs of PID were found at 36 repeats (aged 74, 78, 79, and 87 years), 37 repeats (aged 69 years), 38 repeats (aged 69 and 90 years), and 39 repeats (aged 67, 90, and 95 years). The detailed case histories of an exceptional case from this series will be presented: a 95-year-old man with 39 repeats who did not have classical features of HD. The apparently healthy survival into old age of some individuals with 36-39 repeats suggests that the HD mutation may not always be fully penetrant

Phenotypic characterization of individuals with 30-40 CAG repeats in the Huntington disease (HD) gene reveals HD cases with 36 repeats and apparently normal elderly individuals with 36-39 repeats

Abnormal CAG expansions in the IT-15 gene are associated with Huntington disease (HD). In the diagnostic setting it is necessary to define the limits of the CAG size ranges on normal and HD-associated chromosomes. Most large analyses that defined the limits of the normal and pathological size ranges employed PCR assays, which included the CAG repeats and a CCG repeat tract that was thought to be invariant. Many of these experiments found an overlap between the normal and disease size ranges. Subsequent findings that the CCG repeats vary by 8 trinucleotide lengths suggested that the limits of the normal and disease size ranges should be reevaluated with assays that exclude the CCG polymorphism. Since patients with between 30 and 40 repeats are rare, a consortium was assembled to collect such individuals. AU 178 samples were reanalyzed in Cambridge by using assays specific for the CAG repeats. We have optimized methods for reliable sizing of CAG repeats and show cases that demonstrate the dangers of using PCR assays that include both the CAG and CCG polymorphisms. Seven HD patients had 36 repeats, which confirms that this allele is associated with disease. Individuals without apparent symptoms or signs of PID were found at 36 repeats (aged 74, 78, 79, and 87 years), 37 repeats (aged 69 years), 38 repeats (aged 69 and 90 years), and 39 repeats (aged 67, 90, and 95 years). The detailed case histories of an exceptional case from this series will be presented: a 95-year-old man with 39 repeats who did not have classical features of HD. The apparently healthy survival into old age of some individuals with 36-39 repeats suggests that the HD mutation may not always be fully penetrant

Comparative analysis of phenolic profiles of ovipositional fluid of Rhinusa pilosa (Mecinini, Curculionidae) and its host plant Linaria vulgaris (Plantaginaceae)

Rhinusa pilosa (Gyllenhal) is a highly specific weevil that induces stem galls on the common toadflax Linaria vulgaris Mill. females oviposit the eggs near the apex of a growing shoot. The act of oviposition is accompanied by secretion of an ovipositional fluid, which is considered to be cecidogen, directly involved in gall induction. The remains of cecidogenic fluid were collected from the surface of the oviposition point on the stem. We performed a comparative analysis of the phenolics extracted from cecidogen, the stem and galls of L. vulgaris and adult and larva of R. pilosa by HPLC-DAD. One compound with A (max) at 273, 332 nm (R (t) 30.65 min) was exclusively found in the methanol extract of cecidogen. To further characterize the cecidogen and stem phenolic profiles, we used UHPLC coupled with an OrbiTrap mass analyzer. Among 49 phenolic compounds extracted from both the ovipositional fluid and the plant, protocatechuic acid and two phenolic glycosides were exclusively found in cecidogen: diosmetin-O-acetylrutinoside and an unidentified compound. The unknown compound produced an MS2 base peak at 387 and 327 and 267 m/z base peaks at MS3 and MS4 fragmentation, respectively, and had the molecular formula C32H31O18. The plausible role of phenolic compounds in the induction of gall formation on L. vulgaris is discussed