Kim et al. identify novel genes and disease pathways in the forebrain developmental disorder holoprosencephaly, and show that many cases involve oligogenic inheritance. The findings underline the... Show moreKim et al. identify novel genes and disease pathways in the forebrain developmental disorder holoprosencephaly, and show that many cases involve oligogenic inheritance. The findings underline the roles of Sonic Hedgehog and primary cilia in forebrain development, and show that integrating clinical phenotyping into genetic studies can uncover relevant mutations.Holoprosencephaly is a pathology of forebrain development characterized by high phenotypic heterogeneity. The disease presents with various clinical manifestations at the cerebral or facial levels. Several genes have been implicated in holoprosencephaly but its genetic basis remains unclear: different transmission patterns have been described including autosomal dominant, recessive and digenic inheritance. Conventional molecular testing approaches result in a very low diagnostic yield and most cases remain unsolved. In our study, we address the possibility that genetically unsolved cases of holoprosencephaly present an oligogenic origin and result from combined inherited mutations in several genes. Twenty-six unrelated families, for whom no genetic cause of holoprosencephaly could be identified in clinical settings [whole exome sequencing and comparative genomic hybridization (CGH)-array analyses], were reanalysed under the hypothesis of oligogenic inheritance. Standard variant analysis was improved with a gene prioritization strategy based on clinical ontologies and gene co-expression networks. Clinical phenotyping and exploration of cross-species similarities were further performed on a family-by-family basis. Statistical validation was performed on 248 ancestrally similar control trios provided by the Genome of the Netherlands project and on 574 ancestrally matched controls provided by the French Exome Project. Variants of clinical interest were identified in 180 genes significantly associated with key pathways of forebrain development including sonic hedgehog (SHH) and primary cilia. Oligogenic events were observed in 10 families and involved both known and novel holoprosencephaly genes including recurrently mutated FAT1, NDST1, COL2A1 and SCUBE2. The incidence of oligogenic combinations was significantly higher in holoprosencephaly patients compared to two control populations (P < 10(9)). We also show that depending on the affected genes, patients present with particular clinical features. This study reports novel disease genes and supports oligogenicity as clinically relevant model in holoprosencephaly. It also highlights key roles of SHH signalling and primary cilia in forebrain development. We hypothesize that distinction between different clinical manifestations of holoprosencephaly lies in the degree of overall functional impact on SHH signalling. Finally, we underline that integrating clinical phenotyping in genetic studies is a powerful tool to specify the clinical relevance of certain mutations. Show less
Khan, S.; Amin, F.M.; Christensen, C.E.; Ghanizada, H.; Younis, S.; Olinger, A.C.R.; ... ; Ashina, M. 2019
The origin of migraine pain is unknown, but may involve the dura mater. In unilateral migraine without aura, Khan et al. report that the middle meningeal artery is the only artery with greater... Show moreThe origin of migraine pain is unknown, but may involve the dura mater. In unilateral migraine without aura, Khan et al. report that the middle meningeal artery is the only artery with greater circumference increase on the pain side versus non-pain side, suggesting a meningeal contribution to migraine headache.The origin of migraine pain is unknown but possibly implicates the dura mater, which is pain sensitive in proximity to the meningeal arteries. Therefore, subtle changes in vessel calibre on the head pain side could reflect activation of dural perivascular nociceptors that leads to migraine headache. To test this hypothesis, we measured circumference changes of cranial arteries in patients with cilostazol-induced unilateral migraine without aura using 3 T high resolution magnetic resonance angiography. The middle meningeal artery was of key interest, as it is the main supply of the dura mater. We also measured the superficial temporal and external carotid arteries as additional extracranial segments, and the middle cerebral, the cerebral and cavernous parts of the internal carotid (ICA(cerebral) and ICA(cavernous)), and the basilar arteries as intracranial arterial segments. Magnetic resonance angiography scans were performed at baseline, migraine onset, after sumatriptan, and 27 h after migraine onset. Thirty patients underwent magnetic resonance angiography scans, of which 26 patients developed unilateral attacks of migraine without aura and were included in the final analysis. Eleven patients treated their migraine with sumatriptan while the remaining 15 patients did not treat their attacks with analgesics or triptans. At migraine onset, only the middle meningeal artery exhibited greater circumference increase on the pain side (0.24 0.37 mm) compared to the non-pain side (0.06 0.38 mm) (P = 0.002). None of the remaining arteries revealed any pain-side specific changes in circumference (P > 0.05), but exhibited bilateral dilation. Sumatriptan constricted all extracerebral arteries (P < 0.05). In the late phase of migraine, we found sustained bilateral dilation of the middle meningeal artery. In conclusion, onset of migraine is associated with increase in middle meningeal artery circumference specific to the head pain side. Our findings suggest that vasodilation of the middle meningeal artery may be a surrogate marker for activation of dural perivascular nociceptors, indicating a meningeal site of migraine headache. Show less
Doets, A.Y.; Verboon, C.; Berg, B. van den; Harbo, T.; Cornblath, D.R.; Willison, H.J.; ... ; IGOS Consortium 2018
Recently, Desai et al. described six subjects with deletions in the ATAD3 gene cluster (Desai et al. 2017). Most of these patients died within their first week of life and one died after 7 months,... Show moreRecently, Desai et al. described six subjects with deletions in the ATAD3 gene cluster (Desai et al. 2017). Most of these patients died within their first week of life and one died after 7 months, but one was still alive at 30 years of age. Harel et al. (2016) described three patients with biallellic variations in ATAD3A, one of whom died in the second week of life but the other two were alive at 24 and 26 years, respectively. For pre- and postnatal management it is important to understand why some patients die very early, whereas others seem to have a much milder clinical affect. Show less
Dijk, T. van; Rudnik-Schoneborn, S.; Senderek, J.; Hajmousa, G.; Mei, H.L.; Dusl, M.; ... ; Baas, F. 2017
