Natural History of Hypertrophic Cardiomyopathy in Noonan Syndrome With Multiple Lentigines

BACKGROUND

We aimed to examine clinical features and outcomes of consecutive molecularly characterized patients with Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy.

METHODS

A retrospective, longitudinal multicenter cohort of consecutive children and adults with a genetic diagnosis of Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy between 2002 and 2019 was assembled. We defined a priori 3 different patterns of left ventricular remodeling during follow-up: (1) an increase in ≥15% of the maximal left ventricular wall thickness (MLVWT), both in mm and z-score (progression); (2) a reduction ≥15% of the MLVWT, both in mm and z-score (absolute regression); (3) a reduction ≥15% of the MLVWT z-score with a stable MLVWT in mm (relative regression). The primary study end point was a composite of cardiovascular death, heart transplantation, and appropriate implantable cardioverter defibrillator-shock.

RESULTS

The cohort comprised 42 patients with Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy, with a median age at diagnosis of 3.5 (interquartile range, 0.2-12.3) years. Freedom from primary end point was 92.7% (95% CI, 84.7%-100%) 1 year after presentation and 80.9% (95% CI, 70.1%-90.7%) at 5 years. Patients with MLVWT z-score >13.7 showed reduced survival compared with those with <13.7. During a median follow-up of 3.7 years (interquartile range, 2.6-7.9), absolute regression was the most common type of left ventricular remodeling (n=9, 31%), followed by progression (n=6, 21%), and relative regression (n=6, 21%).

CONCLUSIONS

These findings provide insights into the natural history of left ventricular hypertrophy, and can help inform clinicians regarding risk stratification and clinical outcomes in patients with Noonan syndrome with multiple lentigines and hypertrophic cardiomyopathy.

Growth in children with congenital heart disease

OBJECTIVE

We sought to describe growth in young children with congenital heart disease (CHD) over time.

METHODS

We performed a retrospective matched cohort study, identifying children with CHD in a large primary care network in Pennsylvania, New Jersey, and Delaware and matching them 10:1 with control subjects. The primary endpoint was the difference in mean World Health Organization z score for cases and controls for weight-for-age (WFAZ), length-for-age (LFAZ), weight-for-length (WFLZ), and head circumference-for-age (HCFAZ) at traditional ages for preventive visits, stratified by CHD category.

RESULTS

We evaluated 856 cases: 37 with single ventricle (SV) physiology, 52 requiring complex repair (CR), 159 requiring simple repair (SR), and 608 requiring no repair. For children in the SV, CR, and SR categories, large, simultaneous, and statistically significant (Student's t test P < .05) decreases in WFAZ and LFAZ appeared within the first month of life, peaked near 4 months, and persisted through 24 or 36 months. There were fewer and smaller decreases in the no-repair group between 2 and 18 months. HC data were available between 1 week and 24 months; at those ages, decreases in mean HCFAZ generally paralleled decreases in WFAZ and LFAZ in the SV, CR, and SR groups.

CONCLUSIONS

Children with CHD experience early, simultaneous decreases in growth trajectory across weight, length, and head circumference. The simultaneous decrease suggests a role for altered growth regulation in children with CHD.

An atypical deletion of the Williams-Beuren syndrome interval implicates genes associated with defective visuospatial processing and autism

BACKGROUND

During a genetic study of autism, a female child who met diagnostic criteria for autism spectrum disorder, but also exhibited the cognitive-behavioural profile (CBP) associated with Williams-Beuren syndrome (WBS) was examined. The WBS CBP includes impaired visuospatial ability, an overly friendly personality, excessive non-social anxiety and language delay.

METHODS

Using array-based comparative genomic hybridisation (aCGH), a deletion corresponding to BAC RP11-89A20 in the distal end of the WBS deletion interval was detected. Hemizygosity was confirmed using fluorescence in situ hybridisation and fine mapping was performed by measuring the copy number of genomic DNA using quantitative polymerase chain reaction.

RESULTS

The proximal breakpoint was mapped to intron 1 of GTF2IRD1 and the distal breakpoint lies 2.4-3.1 Mb towards the telomere. The subject was completely hemizygous for GTF2I, commonly deleted in carriers of the classic approximately 1.5 Mb WBS deletion, and GTF2IRD2, deleted in carriers of the rare approximately 1.84 Mb WBS deletion.

CONCLUSION

Hemizygosity of the GTF2 family of transcription factors is sufficient to produce many aspects of the WBS CBP, and particularly implicate the GTF2 transcription factors in the visuospatial construction deficit. Symptoms of autism in this case may be due to deletion of additional genes outside the typical WBS interval or remote effects on gene expression at other loci.