De Novo Mutations Affecting the Catalytic Cα Subunit of PP2A, PPP2CA, Cause Syndromic Intellectual Disability Resembling Other PP2A-Related Neurodevelopmental Disorders.

Type 2A protein phosphatases (PP2As) are highly expressed in the brain and regulate neuronal signaling by catalyzing phospho-Ser/Thr dephosphorylations in diverse substrates. PP2A holoenzymes comprise catalytic C-, scaffolding A-, and regulatory B-type subunits, which determine substrate specificity and physiological function. Interestingly, de novo mutations in genes encoding A- and B-type subunits have recently been implicated in intellectual disability (ID) and developmental delay (DD). We now report 16 individuals with mild to profound ID and DD and a de novo mutation in PPP2CA, encoding the catalytic Cα subunit. Other frequently observed features were severe language delay (71%), hypotonia (69%), epilepsy (63%), and brain abnormalities such as ventriculomegaly and a small corpus callosum (67%). Behavioral problems, including autism spectrum disorders, were reported in 47% of individuals, and three individuals had a congenital heart defect. PPP2CA de novo mutations included a partial gene deletion, a frameshift, three nonsense mutations, a single amino acid duplication, a recurrent mutation, and eight non-recurrent missense mutations. Functional studies showed complete PP2A dysfunction in four individuals with seemingly milder ID, hinting at haploinsufficiency. Ten other individuals showed mutation-specific biochemical distortions, including poor expression, altered binding to the A subunit and specific B-type subunits, and impaired phosphatase activity and C-terminal methylation. Four were suspected to have a dominant-negative mechanism, which correlated with severe ID. Two missense variants affecting the same residue largely behaved as wild-type in our functional assays. Overall, we found that pathogenic PPP2CA variants impair PP2A-B56(δ) functionality, suggesting that PP2A-related neurodevelopmental disorders constitute functionally converging ID syndromes.

Nine Successful Pregnancy Outcomes in a Woman With Vascular Ehlers-Danlos Syndrome: A Case Report and Literature Review.

INTRODUCTION: The vascular form of Ehlers-Danlos syndromes occurs due to alterations in the COL3A1 gene. It has been associated with major vascular and hollow organ complications, leading to increased morbidity and mortality rates with pregnancy. CASE PRESENTATION: We report a woman (gravida 9, para 9) diagnosed with vascular Ehlers-Danlos syndrome in her 70s after bowel rupture. Genetic testing revealed a null mutation in COL3A1 that is predicted to result in haploinsufficiency. Preceding diagnosis, she had 9 pregnancies with minimal complications. DISCUSSION: While no evidence-based guidelines for obstetric care in vascular Ehlers-Danlos syndrome have been well-established, patients often are counseled and followed as high-risk pregnancies. CONCLUSIONS: Null mutations resulting in haploinsufficiency likely have lower pregnancy risks than reported in the literature for vascular Ehlers-Danlos syndrome overall. Thus, understanding the specific COL3A1 mutation may help optimize counseling regarding pregnancy and facilitate decision-making regarding management.

Genetic services plan for Wisconsin.

During 1999-2001, a multidisciplinary group met to develop a plan for the future of genetic services in Wisconsin. The result was The Genetic Services Plan for Wisconsin (available at www.slh.wisc.edu/genetics/stateplan_toc.html), a problem-oriented needs-identification guide to address current and future challenges likely to affect the provision of genetic services in Wisconsin. The Plan is directed to all individuals who have a stake in the future of medical genetic services in Wisconsin. These include, but are not limited to, primary and other health care professionals, genetics professionals, governmental representatives, policy makers, legislators, educators, third-party payers, and current and potential consumers. This article provides an overview of The Genetic Services Plan for Wisconsin (Plan) and highlights the recommendations made for the continuing integration of new genetic knowledge across the continuum of medical care delivery in Wisconsin.