What Is Shprintzen-Goldberg Syndrome?

Shprintzen-Goldberg syndrome (SGS) is an extremely rare connective tissue disorder defined by a combination of craniosynostosis (premature fusion of skull bones), a tall and thin “marfanoid” body type, and abnormalities spanning the skeleton, heart, eyes, and nervous system. Caused by mutations in a gene called SKI, the condition affects the body’s connective tissue so broadly that it can look, at first glance, like several other genetic syndromes. Fewer than about 75 cases have been documented in the medical literature since the syndrome was first formally recognized in 1982, making it one of the rarest named genetic conditions and one that even many physicians have never encountered.

How the Syndrome Was Identified

The earliest clinical description resembling SGS appeared in 1981, but Robert Shprintzen and Robert Goldberg established it as a distinct entity the following year. For decades afterward, the genetic cause remained unknown, and doctors diagnosed it solely by recognizing a characteristic pattern of physical features. That changed in 2012, when two independent research groups identified mutations in the SKI gene on chromosome 1 as the cause. Before that discovery, dozens of patients had been diagnosed based on clinical features alone, and some older cases in the literature may actually represent different conditions that looked similar.

The Physical Features That Define SGS

No single feature is unique to SGS. Instead, diagnosis depends on recognizing a characteristic cluster of anomalies that together distinguish it from other marfanoid syndromes. The craniofacial appearance is often the first clue. A clinical analysis of 37 individuals with SGS found that more than two-thirds had widely spaced eyes (hypertelorism), downward-slanting eyelid openings, a high-arched palate, a small lower jaw, and ears that appear low-set and rotated backward.¹ The skull itself often has a long, narrow shape (dolichocephaly) or a triangular forehead (trigonocephaly), both consequences of craniosynostosis. Bulging eyes (proptosis) and drooping eyelids (ptosis) are common enough to be visible in many reported cases.²

The skeletal features overlap substantially with Marfan syndrome. Long, slender fingers (arachnodactyly), chest-wall deformities like a sunken or protruding breastbone, permanently bent fingers (camptodactyly), scoliosis, and loose joints are all frequently reported.¹ People with SGS tend to be tall and thin relative to their peers, with disproportionately long limbs and a reduced amount of body fat. Hernias, both inguinal and umbilical, are another recurrent finding, reflecting the underlying weakness in connective tissue throughout the body.

Eye Involvement Is Nearly Universal

Vision problems in SGS go well beyond the cosmetic. A systematic review of 44 genetically confirmed cases found that a striking 97 percent had some form of eye abnormality.³ The most frequent findings were hypertelorism (in 43 of 44 patients), downslanting eyelid openings (37 of 44), proptosis (33 of 44), and myopia (10 of 44). Proptosis can be severe enough to require surgical correction and, if left unmanaged, may lead to corneal damage from incomplete eyelid closure. These numbers come from a small total patient pool, so the exact percentages should be interpreted cautiously, but the pattern is clear: ophthalmologic screening is relevant for virtually every person diagnosed with SGS.

Cardiovascular Risks

The heart and blood vessels are a major area of concern. Aortic root dilation, where the first section of the aorta gradually widens, is a recognized feature of SGS and is the same complication that drives much of the medical urgency in Marfan syndrome.⁴ An international cohort study of 29 patients with SGS concluded that the cardiovascular profile is similar enough to Marfan syndrome that the same monitoring and prevention strategy should apply.⁵ In practice, that means yearly echocardiograms to track the size of the ascending aorta and the condition of heart valves, beginning by around age six. The same study recommended avoiding contact sports, competitive athletics, and heavy isometric exercise (think weightlifting) because these activities increase stress on the aortic wall.

Beta-blocker medications, which slow the heart rate and reduce the force of each heartbeat, have been shown in Marfan syndrome to slow the growth of aortic aneurysms. Because SGS shares the same underlying signaling pathway, researchers have suggested that beta-blockers should be considered for SGS patients as well, even before any aortic dilation is visible on imaging.⁵ Mitral valve prolapse and other valve abnormalities also occur and can guide decisions about antibiotic prophylaxis before dental procedures or surgery.

Neurological and Developmental Effects

Low muscle tone (hypotonia) in infancy is one of the earliest and most consistent findings, often preceding any suspicion of a genetic syndrome. Babies with SGS may have difficulty feeding and reaching early motor milestones. Developmental delay and intellectual disability are reported across the published case series, though the degree varies widely. Some individuals have severe cognitive impairment while others fall in the mild range, and at least one recent case report describes a patient with SGS who has no intellectual disability at all, suggesting the spectrum is broader than the older literature implied.⁶

The brain anomalies observed in SGS likely relate to the role that the SKI protein plays in brain development. Research in mice has shown that when the Ski gene is knocked out, the animals develop significant central nervous system defects, and studies in developing brain tissue suggest that the SKI protein helps regulate the transition between neurons and supporting glial cells during fetal brain development.⁷ This helps explain why cognitive outcomes in SGS are variable: the timing and extent of disrupted brain development differ from person to person depending on the specific mutation and other genetic background factors.

The SKI Gene and How It Causes SGS

The SKI gene provides instructions for making a protein that acts as a brake on a signaling pathway called TGF-β. This pathway is active throughout the body and tells cells when to grow, divide, and form connective tissue. When SKI is working normally, it binds to proteins called SMADs and keeps TGF-β signaling in check. In SGS, mutations in a small region of SKI’s first exon interfere with that binding, so the brake is weakened and TGF-β signaling runs higher than it should.⁸ The result is excessive activity in a pathway that controls connective tissue formation throughout the body, which explains why so many different organ systems are affected.

Skin cells taken from people with SGS confirm this mechanism: they show heightened activation of TGF-β signaling and increased expression of the genes that TGF-β normally switches on.⁹ Animal studies reinforce the connection: silencing the SKI equivalent in zebrafish produces abnormalities that mirror the human syndrome, and mice lacking the gene entirely develop midline facial clefts, eye abnormalities, skeletal muscle defects, and digital anomalies that closely resemble what is seen in people with SGS.⁸

The vast majority of SGS cases arise from de novo mutations, meaning the genetic change occurs for the first time in the affected individual rather than being inherited from a parent. In a screening of 19 individuals with SGS, 18 carried identifiable SKI mutations, and most of those were de novo.⁸ Rare exceptions exist: at least one large family with an inherited (dominantly transmitted) mutation has been documented, and one family showed somatic mosaicism, where a parent carried the mutation in some but not all of their cells and unknowingly passed it to more than one child. For genetic counseling purposes, the recurrence risk in siblings of an affected child is generally very low unless parental mosaicism is present.

How SGS Is Told Apart from Marfan and Loeys-Dietz Syndromes

SGS shares so many features with Marfan syndrome and Loeys-Dietz syndrome that distinguishing them on clinical features alone is genuinely difficult. All three involve tall stature, long limbs, aortic dilation, and skeletal abnormalities, and all three are driven by excessive TGF-β signaling, just through different genes. The two features that most reliably set SGS apart from its look-alikes are craniosynostosis and learning disabilities. Neither is a regular feature of classic Marfan syndrome, and while Loeys-Dietz can include craniosynostosis, the pattern of skull and facial findings differs.⁶

In practice, genetic testing is now considered essential for making a definitive diagnosis and for tailoring management. The overlap between SGS, Marfan syndrome, and Loeys-Dietz syndrome is wide enough that clinical features alone can lead to misdiagnosis, and the conditions have somewhat different cardiovascular risk profiles and monitoring needs. A confirmed SKI mutation settles the question and allows clinicians to counsel families accurately about what to watch for and how to plan follow-up. Interestingly, some early cases diagnosed as SGS before genetic testing was available turned out to carry FBN1 mutations (the Marfan gene) instead, underscoring why molecular confirmation matters.

Genotype-Phenotype Patterns Within SGS

Not all SKI mutations produce the same clinical picture. Researchers have identified three mutational “hotspots” within the gene: one cluster affecting amino acids 20 to 35 in the R-SMAD binding domain, a second affecting amino acids 94 to 117 in a region called the Dachshund homology domain, and a third centered on a single amino acid (threonine 180) in the same domain.⁶ Efforts to correlate these mutation groups with specific clinical features are ongoing, but the numbers are still small. The first group accounts for the largest share of reported patients (around 32 of the genetically confirmed cases reviewed), with the second and third groups each contributing a dozen or fewer. As more cases are collected internationally, clearer patterns should emerge about which mutations are more likely to be associated with severe cognitive effects, aggressive aortic dilation, or milder presentations.

Day-to-Day Management

There is no cure for SGS, so treatment is directed at the individual features as they arise. Care typically requires a team spanning genetics, cardiology, orthopedics, ophthalmology, neurology, and sometimes surgery.

For the skeletal system, scoliosis is one of the most functionally significant problems. Because connective tissue laxity makes the spine unusually flexible, bracing is recommended for as long as it remains effective. One orthopedic case report described waiting until the spinal curve reached 80 degrees before performing a single posterior fusion surgery, which achieved a good correction.¹⁰ The approach of delaying surgery and relying on bracing reflects the reality that growing children with connective tissue disorders tend to have higher rates of hardware complications and curve recurrence after spinal surgery, so timing matters.

Cardiovascular monitoring, as discussed earlier, follows the Marfan surveillance model. Dental care also warrants attention: the combination of a high-arched palate, micrognathia, and dental crowding creates orthodontic challenges, and some patients need prophylactic antibiotics before dental procedures because of their cardiac valve status.⁵ Oral findings like maxillary hypoplasia and severe malocclusion are common enough that early involvement of a pediatric dentist familiar with craniofacial conditions is helpful.¹¹

For developmental delays, early intervention with physical therapy, occupational therapy, and speech-language therapy can make a meaningful difference in functional outcomes, particularly when hypotonia is addressed in infancy. The variability in cognitive outcomes means that educational plans need to be individualized; assuming severe disability in every case is not supported by the literature.

Why So Few Cases Are Known

The rarity of SGS raises a practical question: is the syndrome genuinely this uncommon, or is it underdiagnosed? The answer is probably both. Some patients with SGS may be diagnosed instead with Marfan syndrome, Loeys-Dietz syndrome, or nonsyndromic craniosynostosis if genetic testing is not performed. Before the SKI gene was identified in 2012, there was no molecular test to confirm the diagnosis, so earlier case counts are less reliable. The number of documented cases has climbed from roughly 60 at one point to around 75 as genetic testing has become more accessible.¹¹ Broader use of exome and genome sequencing in children with unexplained craniosynostosis and marfanoid features will likely continue to uncover additional cases.

Unusual Associations Still Being Explored

Because so few patients exist, every newly reported case has the potential to expand the known phenotype. One recent case report documented SGS occurring alongside Hirschsprung disease, a condition in which nerve cells are missing from part of the large intestine, causing severe constipation or bowel obstruction.¹¹ Whether this co-occurrence is coincidental or reflects a shared developmental mechanism through TGF-β signaling remains an open question. TGF-β is known to play a role in the development of the enteric nervous system, so a mechanistic link is biologically plausible but far from proven with a single case.

Similarly, the observation that SKI-deficient mice develop not just the expected skeletal and facial features but also skeletal muscle defects and digital anomalies suggests that the full range of human SGS features may be broader than what the small clinical literature has captured so far.⁸ Animal models remain central to understanding SGS because the condition is too rare for large-scale human studies. Zebrafish, in particular, offer a fast and genetically tractable system for testing how specific mutations alter TGF-β signaling and for screening potential drug candidates that might dampen that signaling without unacceptable side effects.⁹ For now, though, treatment remains entirely symptom-driven, and no therapy directly targeting the TGF-β excess has been tested in SGS patients in a clinical trial.

1
PubMed. Shprintzen-Goldberg syndrome: fourteen new patients and a clinical analysis
2
Revista Gaúcha de Odontologia. Shprintzen-goldberg craniosynostosis: craniofacial and oral characteristics, diagnosis, and clinical management of a very rare syndrome
3
PubMed Central. Eye Manifestations of Shprintzen–Goldberg Craniosynostosis Syndrome: A Case Report and Systematic Review
4
PubMed. De novo exon 1 missense mutations of SKI and Shprintzen-Goldberg syndrome: two new cases and a clinical review
5
PubMed Central. Shprintzen-Goldberg syndrome: follow-up of the cardiovascular features in an international cohort of 29 patients with SGS
6
PubMed. Shprintzen – Goldberg syndrome without intellectual disability: A clinical report and review of literature
7
bioRxiv. The protooncogene Ski regulates the neuron-glia switch during development of the mammalian cerebral cortex
8
American Journal of Human Genetics. In-Frame Mutations in Exon 1 of SKI Cause Dominant Shprintzen-Goldberg Syndrome
9
PubMed Central. Mutations in the TGF-β repressor SKI cause Shprintzen-Goldberg syndrome with aortic aneurysm
10
PubMed Central. Scoliosis in Shprintzen–Goldberg Syndrome
11
PubMed Central. A Rare Case of Shprintzen-Goldberg craniosynostosis syndrome with Hirschsprung disorder: Dental characteristics and its Clinical Management