Coexistence of Megaconial Congenital Muscular Dystrophy and Cystinuria: Mimicking Hypotonia-Cystinuria Syndrome

Kara, İlknur Sürücü; Öncül, Ümmühan; Köse, Engi̇n; Turan, Husnu Mutlu; Ceylan, Ahmet Cevdet; Eminoğlu, Fatma Tuba

doi:10.1159/000520502

Cited by 2 publications

(1 citation statement)

References 15 publications

(22 reference statements)

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“…The clinical findings of 35 patients have been previously reported by Chan et al ( 2020 ) and the clinical manifestations of the two children in this study were consistent with previous reports. Except a patient diagnosed with coexistence of Megaconial CMD and Cystinuria (Surucu et al, 2022 ), a total of 50 patients including our two cases are further summarized.…”

Section: Discussionmentioning

confidence: 99%

Large heterozygous deletion and uniparental disomy masquerading as homozygosity inCHKBgene

Zhang

et al. 2023

Molec Gen & Gen Med

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Background CHKB mutations have been described in 49 patients with megaconial congenital muscular dystrophy, which is a rare autosomal recessive disorder, of which 40 patients showed homozygosity. Methods Peripheral blood genomic DNA samples were extracted from patients and their parents and were tested by whole exome sequencing. Quantitative PCR was performed to detect deletion. Single nucleotide polymorphism analysis was performed to identify uniparental disomy. Quantitative PCR and western blot were used to measure the expression level of CHKB in patient 1‐derived immortalized lymphocytes. Mitochondria were observed in lymphocytes by electron microscopy. Results Two unrelated cases born to non‐consanguineous parents were diagnosed with megaconial congenital muscular dystrophy due to apparently homozygous mutations (patient 1: c.225‐2A>T; patient 2: c.701C>T) in the CHKB gene using whole exome sequencing. Quantitative PCR revealed that patient 1 had a large deletion encompassing the CHKB gene, inherited from the mother. Single nucleotide polymorphism analysis revealed patient 2 had paternal uniparental isodisomy containing the CHKB gene. In the immortalized lymphocytes from patient 1, decreased expression of CHKB was revealed by quantitative PCR and western blot, and giant mitochondria were observed using electron microscopy. Conclusion We provide a possibility to detect giant mitochondria in other cells when muscle was not available. Moreover, clinicians should be aware that homozygous variants can be masqueraded by uniparental disomy or large deletions in offspring of non‐consanguineous parents, and excessive homozygosity may be misdiagnosed.

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Section: Discussionmentioning

confidence: 99%