The clinical spectrum of a nonsense mutation in KAT6A: a case report.

KAT6A syndrome is an autosomal dominant genetic disorder associated with intellectual disability due to mutations in the lysine acetyltransferase 6A (KAT6A) gene. There are some differences in phenotype between KAT6A gene variants. This current case report describes a 1-month-old male infant that had a nonsense mutation in the KAT6A gene. Neither of his parents had the mutation. The proband had feeding difficulties and a physical examination revealed the following: moderate dysphagia, hypoplastic laryngeal cartilage, poor audio-visual response, poor head-up ability, no active grasping awareness, microcephaly, high arched palate and he was significantly behind other children of the same age. Echocardiography showed that the foramen ovale was not closed. He was diagnosed with atrial septal defect (ASD) when 2 years old. The patient received ASD repair at 32 months of age. Head colour Doppler ultrasonography and brain magnetic resonance imaging showed cysts in the right ventricle and choroid plexus, which returned to normal at 2 years of age. This current case demonstrates that immediate surgery should be considered in newborns with KAT6A syndrome presenting with a heart malformation. A new KAT6A syndrome phenotype is described in this current case report, which requires early diagnosis and treatment.

A novel UBE2A splice site variant causing intellectual disability type Nascimento.

X-linked intellectual disability type Nascimento (XLID) is a rare disease caused by variants in the ubiquitin-conjugating enzyme E2A gene (UBE2A). Patients with XLID have similar phenotypes, including speech impairments, severe intellectual disability, hearing loss, wide facies, synophrys, generalized hirsutism, and urogenital abnormalities. Till date, only two splice-site variants of the UBE2A gene have been observed in patients with X-linked ID type Nascimento. Here, we report the case of a Chinese boy with a syndrome clinically similar to XLID with speech impairment, severe intellectual disability, and moderate hearing loss. However, different characteristics were also present in the patient, including an inability to maintain his head in an upright posture. Both of the patient's palms have a single transverse palmar crease. Subsequent whole-exome sequencing revealed a novel splice site variant in UBE2A (c.241 + 1 G > A). Our study not only expands the variant spectrum and clinical characteristics of UBE2A deficiency syndrome but also provides clinical evidence for genetic diagnoses.