TBC1D24-related familial infantile multifocal myoclonus: Description of a new Chinese pedigree with a 20 year follow up.

INTRODUCTION: Disorders associated with mutations in the Tre2/Bub2/Cdc16 (TBC)1 domain family member 24 gene (TBC1D24) present a wide range of phenotypes, ranging from mild to fatal seizure diseases, non-syndromic deafness, and complex syndromes such as deafness, onychodystrophy, osteodystrophy, and mental retardation(DOOR syndrome). In this study, we introduce three siblings of a previously unreported Chinese family with familial infantile myoclonic epilepsy caused by a homozygous TBC1D24 mutation. METHODS: Genomic DNA was extracted from whole blood of the proband, his parents, and sisters. TBC1D24 exomes were sequenced by whole exome sequencing then analyzed by genetic analysis with Sanger sequencing validation. The patients were followed up for more than 20 years to summarize their clinical features. RESULTS: Genetic analysis identified a homozygous TBC1D24 mutation (c.241_252del12) in the proband and his sisters. Prediction models suggest that the mutation leads to an alteration in the properties and structure of the TBC1D24 protein, especially in the folding direction of the loop region, which is likely to decrease protein activity. The patients manifested with early-onset myoclonic epilepsy, were prone to status epilepticus, and seizures only occurred during wakefulness. Imaging characteristics included cerebellar atrophy and abnormal cerebellar signals. CONCLUSION: We report a pedigree case of infantile myoclonic epilepsy caused by a homozygous TBC1D24 mutation. Our long-term clinical follow-up not only enriches the clinical phenotype of the disease, but also provides a clinical experience for the early diagnosis and clinical treatment of the disease.

[Clinical and genetic analysis of a newborn with hypoparathyroidism, sensorineural hearing loss, and renal dysplasia syndrome].

OBJECTIVE: To analyze the clinical phenotype and genetic basis for a male neonate featuring hypoparathyroidism, sensorineural hearing loss, and renal dysplasia (HDR) syndrome. METHODS: The child was subjected to genome-wide copy number variation (CNVs) analysis and whole exome sequencing (WES). Clinical data of the patient was analyzed. A literature review was also carried out. RESULTS: The patient, a male neonate, had presented with peculiar facial appearance, simian crease and sacrococcygeal mass. Blood test revealed hypocalcemia, hypoparathyroidism. Hearing test suggested bilateral sensorineural deafness. Doppler ultrasound showed absence of right kidney. Copy number variation sequencing revealed a 12.71 Mb deletion at 10p15.3-p13 (chr10: 105 001_12 815 001) region. WES confirmed haploinsufficiency of the GATA3 gene. With supplement of calcium and vitamin D, the condition of the child has improved. CONCLUSION: The deletion of 10p15.3p13 probably underlay the HDR syndrome in this patient.

Clinical report of a neonate carrying a large deletion in the 10p15.3p13 region and review of the literature.

BACKGROUND: Terminal deletion of chromosome 10p is a rare chromosomal abnormality. We report a neonatal case with a large deletion of 10p15.3p13 diagnosed early because of severe clinical manifestations. CASE PRESENTATION: Our patient presented with specific facial features, hypoparathyroidism, sen sorineural deafness, renal abnormalities, and developmental retardation, and carried a 12.6 Mb deletion in the 10p15.3 p13 region. The terminal 10p deletion involved in our patient is the second largest reported terminal deletion reported to date, and includes the ZMYND11 and GATA3 genes and a partial critical region of the DiGeorge syndrome 2 gene (DGS2). CONCLUSION: On the basis of a literature review, this terminal 10p deletion in the present case is responsible for a specific contiguous gene syndrome. This rare case may help the understanding of the genotype-phenotype spectrum of terminal deletion of chromosome 10p.