Perspectives on Overgrowth syndromes

Tatton-Brown-Rahman syndrome: Six individuals with novel features

Tatton-Brown Rahman syndrome (TBRS) is an overgrowth-intellectual disability syndrome caused by heterozygous variants in DNMT3A. Seventy-eight individuals have been reported with a consistent phenotype of somatic overgrowth, mild to moderate intellectual disability, and similar dysmorphisms. We present six individuals with TBRS, including the youngest individual thus far reported, first individual to be diagnosed with tumor testing and two individuals with variants at the Arg882 domain, bringing the total number of reported cases to 82. Patients reported herein have additional clinical features not previously reported in TBRS. One patient had congenital diaphragmatic hernia. One patient carrying the recurrent p.Arg882His DNMT3A variant, who was previously reported as having a phenotype due to a truncating variant in the CLTC gene, developed a ganglioneuroblastoma at 18 months and T-cell lymphoblastic lymphoma at 6 years of age. Four patients manifested symptoms suggestive of autonomic dysfunction, including central sleep apnea, postural orthostatic hypotension, and episodic vasomotor instability in the extremities. We discuss the molecular and clinical findings in our patients with TBRS in context of existing literature.

3.2 Mb microdeletion in chromosome 7 bands q22.2-q22.3 associated with overgrowth and delayed bone age

We report a patient with mental retardation, epilepsy, overgrowth, delayed bone age, peculiar facial features, corpus callosum hypoplasia, enlarged cisterna magna and right cerebellar hypoplasia. Array-CGH analysis revealed the presence of a de novo 3.2 Mb interstitial deletion of the long arm of chromosome 7 involving bands q22.2-q22.3. The rearrangement includes 15 genes and encompasses a genomic region that represents a site of frequent loss of heterozygosity in myeloid malignancies. Four genes are implicated in the control of cell cycle: SRPK2, MLL5, RINT1 and LHFPL3. Haploinsufficiency of these genes might therefore be associated with overgrowth and could confer susceptibility to cancers or other tumours, so that attention to this possibility would be appropriate during regular medical review. In conclusion, array-CGH analysis should be performed in patients with overgrowth where the known causes have already been excluded, because some still unclassified overgrowth syndromes may be caused by subtle genomic imbalances.

Overgrowth conditions: a diagnostic and therapeutic conundrum

Over the past five decades, one of the major problems in the treatment of overgrowth syndromes of the hand has been classification. Currently, a number of specific conditions with known natural histories have been delineated and reviewed. Treatment is highly individualized. Amputation is still recommended for grotesque deformities of the upper limb. Early aggressive surgery, when indicated, will improve contour, function, and appearance. Specific therapeutic techniques include radical debulking, microvascular neurolysis, vascular reconstruction, epiphysiodesis, and, in some cases, thumb or digit replacement. Long-term outcomes remain in the good-to-fair range and are dependent upon the condition, reconstructive techniques employed, age of patient, and the severity of deformity.

Retinoblastoma, pinealoma, and mild overgrowth in a boy with a deletion ofRB1 and neighbor genes on chromosome 13q14

We report on a 10-year-old boy with a normal karyotype and a chromosome 13q14 deletion of the retinoblastoma gene (RB1) by fluorescence in situ hybridization (FISH). He showed subtle signs of overgrowth, including macrocephaly, hepatomegaly, and inguinal hernia. The boy also had cryptorchism and mild developmental delay. In his first months of life, variant Wiedemann-Beckwith syndrome was tentatively suspected and he was included in a careful tumor prevention program. At the age of 11 months, bifocal retinoblastoma of the left eye was diagnosed. Pinealoma was suspected at the age of 19 months and was removed by neurosurgery at the age of 29 months. At 4 years and 4 months, the deletion of the RB1 gene was suspected on clinical grounds and was diagnosed by FISH and molecular studies. At that time, he was a near-normal healthy playful kindergarten child, height 107 cm (-0.3 SD), OFC 52.5 cm (+0.8 SD), developmental age 3-3.5 years. The combination of retinoblastoma, pinealoma, and deletion of the RB1 gene diagnosed by FISH has not been reported previously. The deletion spans at least 370-420 kb in size and is predicted to include proximal and distal neighbor genes. This report may assist in establishing the clinical signs of the contiguous gene syndrome at the RB1 locus on 13q14.

Recognition and management of childhood cancer syndromes: a systems approach

Recognition of congenital anomalies that predispose to childhood cancer allows for the institution of a cancer surveillance program, identification of relatives with increased cancer risk, and recurrence risk counseling. In this article, a systems approach to the diagnosis of 21 childhood cancer syndromes is set forth in the format of the pediatric physical examination. In the second part of this article, guidelines are presented for genetic testing, cancer screening, and genetic counseling for the 21 cancer syndromes.

Proteus syndrome: diagnostic criteria, differential diagnosis, and patient evaluation

Proteus syndrome is a complex disorder comprising malformations and overgrowth of multiple tissues. The disorder is highly variable and appears to affect patients in a mosaic manner. This intrinsic variability has led to diagnostic confusion associated with a dearth of longitudinal data on the natural history of Proteus syndrome. To clarify some of these issues, a workshop on Proteus syndrome was held in March 1998 at the National Institutes of Health, and participants developed recommendations for diagnostic criteria, differential diagnosis, and guidelines for the evaluation of patients. This is a review of those recommendations.