Benign paroxysmal torticollis of infancy (BPTI) is a disorder characterized by recurrent episodes of head tilt secondary to cervical dystonia. Attacks are often accompanied by vomiting, pallor, and ataxia, settling spontaneously within hours or days. Episodes begin within the first 12 months of life and resolve by 5 years. We report four patients with BPTI. Symptoms started from 3 months of age, with head tilting lasting between 10 minutes and 2 months; the shorter episodes were followed by vomiting, apathy, and unsteadiness. Head tilt became less prominent after infancy, replaced by vertigo and eventually by migraine headaches. Two patients came from a kindred with familial hemiplegic migraine linked to CACNA1A mutation. BPTI may be regarded as a migraine aura equivalent. The syndrome poses interesting questions regarding varying phenotypic expression of calcium channelopathies at different stages of development.

We identified two novel heteroplasmic mitochondrial DNA point mutations in the gene encoding the ND5 subunit of complex I: a 12770A-->G transition identified in a patient with MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) and a 13045A-->C transversion in a patient with a MELAS/Leber's hereditary optic neuropathy/Leigh's overlap syndrome. Biochemical analysis of muscle homogenates showed normal or very mildly reduced complex I activity. Histochemistry was normal. Our observations add to the evidence that mitochondrial ND5 protein coding gene mutations frequently associate with the MELAS phenotype, and it highlights the role of complex I dysfunction in MELAS.

Benign paroxysmal torticollis of infancy (BPTI) is a disorder characterized by recurrent episodes of head tilt secondary to cervical dystonia. Attacks are often accompanied by vomiting, pallor, and ataxia, settling spontaneously within hours or days. Episodes begin within the first 12 months of life and resolve by 5 years. We report four patients with BPTI. Symptoms started from 3 months of age, with head tilting lasting between 10 minutes and 2 months; the shorter episodes were followed by vomiting, apathy, and unsteadiness. Head tilt became less prominent after infancy, replaced by vertigo and eventually by migraine headaches. Two patients came from a kindred with familial hemiplegic migraine linked to CACNA1A mutation. BPTI may be regarded as a migraine aura equivalent. The syndrome poses interesting questions regarding varying phenotypic expression of calcium channelopathies at different stages of development.

Mutations in GJA12 have been shown to cause Pelizaeus-Merzbacher-like disease (PMLD). We present two additional patients from one family carrying a homozygous frameshift mutation in GJA12. Both presented initially with nystagmus. The older girl developed ataxia first, then progressive spastic ataxia. The younger boy suffered from severe sensory neuropathy. Magnetic resonance imaging (MRI) of both children showed progressive demyelination in addition to dysmyelination, and also characteristic brainstem abnormalities. In children with nystagmus, ataxia and dysmyelination, mutation analysis of GJA12 should be considered early, especially if inheritance is autosomal recessive.

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Infantile bilateral striatal necrosis (IBSN) is characterized by a dystonic movement disorder and basal ganglia imaging abnormalities. Acute IBSN often occurs after upper respiratory tract infections although no specific micro-organism which may cause IBSN has been identified. We present 2 children (1 year 2 months and 4 years) with acute IBSN after clinical pharyngitis. Both IBSN patients had serological evidence of recent beta-haemolytic streptococcal infection. Due to the association of post-streptococcal disorders with anti-basal ganglia antibodies (ABGA), we examined both patients for anti-neuronal antibodies. For comparison, 20 children with dystonia (9 females, 11 males; mean age 4 years 1 month), and 20 children with uncomplicated streptococcal infection (12 females, 8 males; mean age 5 years 9 months) were examined. Both IBSN patients had antibodies reactive against basal ganglia constituents of molecular weight 40 kDa. Immunohistochemistry showed antibody reactivity against large striatal neurons only. Other anti-neuronal antibodies were negative, supporting striatal specificity. All controls were negative for ABGA. Acute IBSN is part of the poststreptococcal autoimmune neuropsychiatric spectrum. An autoimmune aetiology should be considered in this phenotype, as immunomodulatory therapies may reduce morbidity and mortality.

Atypical Spitzoid melanocytic tumors are diagnostically challenging. Many studies have suggested various genomic markers to improve classification and prognostication. We aimed to assess whether next-generation sequencing studies using the Tempus xO assay assessing mutations in 1711 cancer-related genes and performing whole transcriptome mRNA sequencing for structural alterations could improve diagnostic agreement and accuracy in assessing neoplasms with Spitzoid histologic features. Twenty expert pathologists were asked to review 70 consultation level cases with Spitzoid features, once with limited clinical information and again with additional genomic information. There was an improvement in overall agreement with additional genomic information. Most significantly, there was increase in agreement of the diagnosis of conventional melanoma from moderate (κ=0.470, SE=0.0105) to substantial (κ=0.645, SE=0.0143) as measured by an average Cohen κ. Clinical follow-up was available in all 70 cases which substantiated that the improved agreement was clinically significant. Among 3 patients with distant metastatic disease, there was a highly significant increase in diagnostic recognition of the cases as conventional melanoma with genomics (P<0.005). In one case, none of 20 pathologists recognized a tumor with BRAF and TERT promoter mutations associated with fatal outcome as a conventional melanoma when only limited clinical information was provided, whereas 60% of pathologists correctly diagnosed this case when genomic information was also available. There was also a significant improvement in agreement of which lesions should be classified in the Spitz category/WHO Pathway from an average Cohen κ of 0.360 (SE=0.00921) to 0.607 (SE=0.0232) with genomics.

The current classification of Spitz neoplasms in the World Health Organization (WHO), Fourth Edition defines Spitz neoplasms as melanocytic proliferations with characteristic Spitz morphology and a Spitz-associated genomic fusion or HRAS mutation. In contrast, melanocytic neoplasms with BRAF mutations are considered typical of common acquired nevi, dysplastic nevi, and melanomas from intermittent sun-damaged skin. However, increased utilization of ancillary testing methods such as BRAF V600E immunohistochemistry and sequencing studies have made apparent a subgroup of benign-grade and intermediategrade melanocytic neoplasms with Spitzoid morphology that harbor BRAF V600E mutations. We refer to these cases as BRAF mutated and morphologically Spitzoid (BAMS) nevi and tumors. Two experienced dermatopathologists reviewed a series of 36 BAMS nevi/tumors. Cases in which a diagnosis of melanoma was favored were excluded. The histomorphologic, clinical, and molecular findings were assessed by immunohistochemistry, fluorescence in situ hybridization, and next-generation sequencing using validated gene panels. Characteristics of BAMS nevi/tumors were compared with a control set of Spitz tumors with previously reported fusion proteins. BAMS nevi/tumors had a decreased proportion of Kamino bodies (P = 0.03) and a higher proportion of cytoplasmic pigmentation (P < 0.00001). There were no differences in other morphologic features such as the silhouette, epidermal hyperplasia, pagetosis, and cytologic atypia compared with fusion-induced Spitz tumors. In 6/17 cases where nextgeneration sequencing studies were available, recurrent mutations in the KMT gene family were seen. This was higher than the proportion of such mutations seen in fusion Spitz tumors and lower than the frequency in cutaneous melanoma.