A special association between Charcot-Marie-Tooth type 1A disease and relapsing remitting multiple sclerosis.

BACKGROUND: Central nervous system involvement has been reported in different subtypes of Charcot-Marie-Tooth (CMT) diseases. The increasing number of cases with CMT and MS may provide further information about the common pathway of demyelination and MS pathogenesis. CASE PRESENTATION: We report the case of a 21-year-old woman with CMT1A and MS. Bilateral rest and intention tremor, steroid associated psychotic episodes, and severe disability at an early age were unexpected aspects of this case. CONCLUSION: PMP22, the target protein in CMT1A, shares partial homology with other CNS proteins. PMP22 gene might be relevant to a common pathway of the demyelinating process.

Molecular characterization of near-complete trisomy 17p syndrome from inverted duplication in association with cryptic deletion of 17pter.

Trisomy of the short arm of chromosome 17 (T17P) is a genomic disorder presenting with growth retardation, motor and mental retardation and constitutional physical anomalies including congenital heart defects. Here we report a case of near-complete T17P of which the genomic dosage aberrations were delineated by chromosomal microarray along with conventional diagnostic modalities. A 9-year-old Korean boy was admitted because of esophageal obstruction. He showed clinical manifestations of T17P, along with atypical features of scoliosis, corpus callosum agenesis, and seizure. Chromosome analyses revealed an inverted duplication of the chromosomal segment between 17p11.2 and 17p13.3. Chromosomal microarray revealed a duplication of the most of the short arm of chromosome 17 (size ~19.09 Mb) along with a cryptic deletion of a small segment of 17p terminal end (17pter) (~261 Kb). This is the first report of molecular characterization of near-complete T17P from inverted duplication in association with 17pter microdeletion. The fine delineation of the extent of genomic aberration by SNP-based microarray could help us better understand the molecular mechanism and genotype-phenotype correlations in T17P syndrome.

Chromosomal microarray analysis of consecutive individuals with autism spectrum disorders or learning disability presenting for genetic services.

Chromosomal microarray analysis is now commonly used in clinical practice to identify copy number variants (CNVs) in the human genome. We report our experience with the use of the 105 K and 180K oligonucleotide microarrays in 215 consecutive patients referred with either autism or autism spectrum disorders (ASD) or developmental delay/learning disability for genetic services at the University of Kansas Medical Center during the past 4 years (2009-2012). Of the 215 patients [140 males and 75 females (male/female ratio=1.87); 65 with ASD and 150 with learning disability], abnormal microarray results were seen in 45 individuals (21%) with a total of 49 CNVs. Of these findings, 32 represented a known diagnostic CNV contributing to the clinical presentation and 17 represented non-diagnostic CNVs (variants of unknown significance). Thirteen patients with ASD had a total of 14 CNVs, 6 CNVs recognized as diagnostic and 8 as non-diagnostic. The most common chromosome involved in the ASD group was chromosome 15. For those with a learning disability, 32 patients had a total of 35 CNVs. Twenty-six of the 35 CNVs were classified as a known diagnostic CNV, usually a deletion (n=20). Nine CNVs were classified as an unknown non-diagnostic CNV, usually a duplication (n=8). For the learning disability subgroup, chromosomes 2 and 22 were most involved. Thirteen out of 65 patients (20%) with ASD had a CNV compared with 32 out of 150 patients (21%) with a learning disability. The frequency of chromosomal microarray abnormalities compared by subject group or gender was not statistically different. A higher percentage of individuals with a learning disability had clinical findings of seizures, dysmorphic features and microcephaly, but not statistically significant. While both groups contained more males than females, a significantly higher percentage of males were present in the ASD group.

Effectiveness of Real-Time Quantitative PCR Compare to Repeat PCR for the Diagnosis of Charcot-Marie-Tooth Type 1A and Hereditary Neuropathy with Liability to Pressure Palsies

The majority of cases of Charcot-Marie-Tooth type 1A (CMT1A) and of hereditary neuropathy with a liability to pressure palsies (HNPP) are the result of heterozygosity for the duplication or deletion of peripheral myelin protein 22 gene (PMP22) on 17p11.2. Southern blots, pulsed-field gel electrophoresis (PFGE), fluorescence in situ hybridization (FISH) and polymorphic marker analysis are currently used diagnostic methods. But they are time-consuming, labor-intensive and have some significant limitations. We describe a rapid real- time quantitative PCR method for determining gene copy number for the identification of DNA duplication or deletion occurring in CMT1A or HNPP and compare the results obtained with REP-PCR. Six patients with CMT1A and 14 patients with HNPP [confirmed by Repeat (REP) -PCR], and 16 patients with suspicious CMT1A and 13 patients with suspicious HNPP [negative REP-PCR], and 15 normal controls were studied. We performed REP-PCR, which amplified a 3.6 Kb region (including a 1.7Kb recombination hotspot), using specific CMT1A-REP and real-time quantitative PCR on the LightCycler system. Using a comparative threshold cycle (Ct) method and beta-globin as a reference gene, the gene copy number of the PMP22 gene was quantified. The PMP22 duplication ratio ranged from 1.35 to 1.74, and the PMP22 deletion ratio from 0.41 to 0.53. The PMP22 ratio in normal controls ranged from 0.81 to 1.12. All 6 patients with CMT1A and 14 patients with HNPP confirmed by REP-PCR were positive by real-time quantitative PCR. Among the 16 suspicious CMT1A and 13 suspicious HNPP with negative REP-PCR, 2 and 4 samples, respectively, were positive by real-time quantitative PCR. Real-time quantitative PCR is a more sensitive and more accurate method than REP-PCR for the detection of PMP22 duplications or deletions, and it is also faster and easier than currently available methods. Therefore, we believe that the real-time quantitative method is useful for diagnosing CMT1A and HNPP.

Hereditary Neuropathy with Liability to Pressure Palsy in a Family: A Case Report

We report a family with autosomal dominant hereditary neuropathy having a liability to pressure palsy, which was confirmed by DNA analysis. A 5-year-old boy had been suffering from a left upper extremity weakness after falling sleeping with his head on his arm. Upon examination 2 months after the episode, the boy reported that he had a mild weakness on the left distal portion of his arm. Deep tendon reflexes on both the upper extremities were absent. He did not have any sensory disturbances. No definite family history of recurrent pressure palsy was taken. A nerve conduc-tion study and EMG demonstrated a widespread demyelinating sensorimotor polyneuropathy in all extremities. We analyzed DNA deletion, which revealed an abnormal deletion of the peripheral myelin protein 22 (PMP-22) gene in the chromosome 17p11.2. Of the patient and his mother.

Hereditary Neuropathy with Liability to Pressure Palsy in a Family: A Case Report

We report a family with autosomal dominant hereditary neuropathy having a liability to pressure palsy, which was confirmed by DNA analysis. A 5-year-old boy had been suffering from a left upper extremity weakness after falling sleeping with his head on his arm. Upon examination 2 months after the episode, the boy reported that he had a mild weakness on the left distal portion of his arm. Deep tendon reflexes on both the upper extremities were absent. He did not have any sensory disturbances. No definite family history of recurrent pressure palsy was taken. A nerve conduc-tion study and EMG demonstrated a widespread demyelinating sensorimotor polyneuropathy in all extremities. We analyzed DNA deletion, which revealed an abnormal deletion of the peripheral myelin protein 22 (PMP-22) gene in the chromosome 17p11.2. Of the patient and his mother.