Clinical description, molecular delineation and genotype–phenotype correlation in 340 patients with KBG syndrome: addition of 67 new patients

Background

KBG syndrome is a highly variable neurodevelopmental disorder and clinical diagnostic criteria have changed as new patients have been reported. Both loss-of-function sequence variants and large deletions (copy number variations, CNVs) involvingANKRD11cause KBG syndrome, but no genotype–phenotype correlation has been reported.

Methods

67 patients with KBG syndrome were assessed using a custom phenotypical questionnaire. Manifestations present in >50% of the patients and a ‘phenotypical score’ were used to perform a genotype–phenotype correlation in 340 patients from our cohort and the literature.

Results

Neurodevelopmental delay, macrodontia, triangular face, characteristic ears, nose and eyebrows were the most prevalentf (eatures. 82.8% of the patients had at least one of seven main comorbidities: hearing loss and/or otitis media, visual problems, cryptorchidism, cardiopathy, feeding difficulties and/or seizures. Associations found included a higher phenotypical score in patients with sequence variants compared with CNVs and a higher frequency of triangular face (71.1% vs 42.5% in CNVs). Short stature was more frequent in patients with exon 9 variants (62.5% inside vs 27.8% outside exon 9), and the prevalence of intellectual disability/attention deficit hyperactivity disorder/autism spectrum disorder was lower in patients with the c.1903_1907del variant (70.4% vs 89.4% other variants). Presence of macrodontia and comorbidities were associated with larger deletion sizes and hand anomalies with smaller deletions.

Conclusion

We present a detailed phenotypical description of KBG syndrome in the largest series reported to date of 67 patients, provide evidence of a genotype–phenotype correlation between some KBG features and specificANKRD11variants in 340 patients, and propose updated clinical diagnostic criteria based on our findings.

Sodium channel blockers for the treatment of epilepsy in CDKL5 deficiency disorder: Findings from a multicenter cohort

OBJECTIVE

This study was aimed to analyze the effectiveness of sodium channel blockers (SCBs) in CDKL5 deficiency disorder (CDD)-related epilepsy.

METHODS

A retrospective, observational study was performed, including patients with CDD diagnosis evaluated between 2016 and 2019 at three tertiary Epilepsy Centers. Demographic, electroclinical and genetic features, as well as ASM treatments and their outcomes were analyzed, with special focus on SCBs.

RESULTS

Twenty-one patients evaluated at three tertiary Epilepsy Centers were included, of which 19 presented with epilepsy (90.5%); all had pathogenic mutations of CDKL5. Six patients (31.6%) were classified as SCB responders (more than 50% reduction), four being currently seizure free (mean seizure-free period of 8 years). Most frequent SCB drugs were oxcarbazepine (OXC), carbamazepine (CBZ), and lacosamide (LCM). None of them presented relevant adverse events. In contrast, three patients showed seizure aggravation in the non-responder group. When comparing both groups, responders had statistically significant younger age at SCB treatment and epilepsy onset, higher proportion of focal epileptiform activity and less frequent history of West syndrome.

CONCLUSIONS

The results of this study indicate that treatment with SCBs might be effective and safe in a subset of patients with CDD-related epilepsy.

Incontinentia pigmenti: MR demonstration of brain changes

PURPOSE

To describe the MR findings in eight girls and women with incontinentia pigmenti, from two families. Four had skin lesions and neurologic disease, and four had only skin lesions.

METHODS

Eight patients had physical examination, family history, electroencephalogram and MR examination of the brain. MR was repeated in the two cases with more severe changes several years after the first study.

RESULTS

MR revealed brain changes only in the four patients who had neurologic disease associated with the cutaneous lesions of incontinentia pigmenti. Abnormalities were located in the cerebral hemisphere contralateral to the most affected side of the body. In two cases, the MR changes were subjacent to the scalp areas where the most severe cutaneous lesions were located in the neonatal period. Hypoplasia of the corpus callosum, probably secondary to atrophy of one or both cerebral hemispheres, and abnormal signal and atrophy of the lateral regions of one of the cerebellar hemispheres also were found in all four cases. Although the changes were seen in both the T1- and T2-weighted images, they were most evident in the latter. The four patients in the fourth stage who had only cutaneous lesions without neurologic problems did not reveal any MR abnormalities.

CONCLUSIONS

This study demonstrates MR signal changes and focal atrophy of the cerebrum, cerebellum, and corpus callosum in patients with incontinentia pigmenti and neurologic disorders. The MR images appear normal in patients with incontinentia pigmenti who have no neurologic abnormalities.