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Background Germline mutations of the PTEN gene are responsible for several PTEN hamartoma tumor syndromes. They are also implicated as a cause of macrocephaly and mild to severe developmental delay, regardless of the presence or absence of hamartomas in childhood. Nevertheless, because of limited information, the clinical features present during childhood in patients with a PTEN mutation are yet to be elucidated. Methods PTEN mutations were investigated by multiplex targeted sequencing of genomic DNA from 33 children with increased head circumference (>+2 SD) and developmental delay. The clinical features of all the patients with a PTEN mutation were abstracted by dysmorphologists. Results We have identified six children with a PTEN mutation. Clinical dissection of these six patients, in addition to patient reports in the literature, revealed distinctive facial features that included frontal bossing, dolichocephaly, horizontal eyebrows, and a depressed nasal bridge. Macrocephaly (+3.2 to +6.0 SD) was noticeable compared to their height (−0.8 to +2.1 SD), and the difference in the SD value of head circumference and height was more than 3 SD in all patients. Conclusion The presence of distinctive facies, extreme macrocephaly with normal to mildly high stature, and developmental delay may be useful for identifying patients with a PTEN mutation in childhood. Early identification of patients with a PTEN mutation would help uncover the natural course of tumor development in this group of individuals who have a possible predisposition to cancer, and be important for the development of an optimal surveillance strategy.

Introduction Filamin A (FLNA) is located in Xq28, and encodes the actin binding protein, filamin A. A mutation in FLNA is the most common cause of periventricular nodular heterotopia (PVNH), but a clear phenotype-genotype correlation has not been established. Indeed, some patients with a FLNA mutation have recently been shown to additionally have Ehlers-Danlos-like collagenopathy or macrothrombocytopenia. In an attempt to establish a clearer correlation between clinical symptoms and genotype, we have investigated a phenotype that involves thrombocytopenia in a patient with a truncation of the FLNA gene. Case report We present the case of a 4-year-old girl who, at birth, showed a ventral hernia. At 2 months of age, she was diagnosed with patent ductus arteriosus (PDA) and aortic valve regurgitation. At 11 months, she underwent ligation of the PDA. She was also diagnosed with diaphragmatic eventration by a preoperative test. At 19 months, motor developmental delay was noted, and brain MRI revealed bilateral PVNH with mega cisterna magna. Presently, there is no evidence of epilepsy, intellectual disability or motor developmental delay. She has chronic, mild thrombocytopenia, and a platelet count that transiently decreases after viral infection. Dilation of the ascending aorta is progressing gradually. Genetic testing revealed a de novo nonsense heterozygous mutation in FLNA (NM_001456.3: c.1621G > T; p.Glu541Ter). Immunofluorescence staining of a peripheral blood smear showed a lack of filamin A expression in 21.1% of her platelets. These filamin A-negative platelets were slightly larger than her normal platelets. Conclusion Our data suggests immunofluorescence staining of peripheral blood smears is a convenient diagnostic approach to identify patients with a FLNA mutation, which will facilitate further investigation of the correlation between FLNA mutations and patient phenotype.

Patients with a mutation at Arg756 in ATP1A3 have been known to exhibit a distinct phenotype, characterized by prolonged weakness and encephalopathy, triggered by febrile illness. With only eight reports published to date, more evidence is required to correlate clinical features with a mutation at Arg756. Here we report an additional case with an Arg756Cys mutation in ATP1A3. A four-year-old boy showed mild developmental delay with recurrent paroxysmal episodes of weakness and encephalopathy from nine months of age. Motor deficits, which included bilateral hypotonia, ataxia, dysmetria, limb incoordination, dysarthria, choreoathetosis, and dystonia, were observed from one year and three months. Whole-exome sequencing detected a heterozygous de novo variant at c.2266C>T (p.Arg756Cys) in ATP1A3. The episodic course and clinical features of this case were consistent with previously reported cases with mutations at Arg756. Furthermore, his phenotype of marked ataxia was more similar to that of an Arg756Cys patient with relapsing encephalopathy and cerebellar ataxia syndrome, than to those with Arg756His and Arg756Leu mutations. This report therefore provides evidence of genotype-phenotype correlations in ATP1A3-related disorders as well as in patients with mutations at Arg756 in ATP1A3.