January 2026 Research Update

This month added a clearer picture of what happens to fractures and health-care use after people start asfotase alfa (an enzyme replacement) in everyday care. In a US claims analysis, fewer people had fractures in the year after starting asfotase alfa, and fracture event rates tended to drop further with longer follow-up [1] . A separate multicenter report from Saudi Arabia also described clinical and X-ray improvements in many treated patients, but not everyone responded the same way, especially in very severe early-onset cases [2] .

The largest human dataset this month came from insurance claims, which can track billed fractures and services over time but cannot fully explain why changes happen. In that analysis of 149 people, the proportion with at least one fracture fell from 18.1% in the 12 months before treatment to 8.1% in the 12 months after starting asfotase alfa, and fragility fracture rates also decreased [1] . The same dataset reported that some types of follow-up services, like imaging and bone density testing, were billed less often after treatment started, and opioid claims showed possible decreases in some people who used opioids at baseline [1] .

The Saudi case series helps show what response can look like in a setting with many children and very early-onset disease. Thirteen of 19 patients received asfotase alfa, and alkaline phosphatase levels rose strongly after treatment, alongside reported growth gains and radiographic improvements in many patients [2] . At the same time, a few patients were described as non-responders or had regression after an initial response, and the report noted that early mortality and short treatment duration in perinatal cases may have affected outcomes [2] .

For patients and caregivers, these studies mainly add real-world context about how asfotase alfa use lines up with fracture patterns and day-to-day health-care needs, rather than proving what the treatment will do for any one person. The claims study suggests that, in routine care, billed fractures were less common after starting asfotase alfa, and some fracture-related care (like imaging) was used less often, which may reflect fewer events or changing follow-up patterns [1] . The case series reminds readers that responses can vary and that very early-onset forms can have serious outcomes despite treatment, so averages from larger datasets may not capture every situation [2] .

What remains uncertain is how much of the fracture and medication changes in claims data are directly caused by treatment versus differences in who gets treated, how they are monitored, and how events are coded in billing systems [1] . Even with those limits, this month strengthens the practical message that researchers are now measuring outcomes that matter to daily life, such as fractures, pain medication use, and growth, not only lab values and X-rays [1] .

This month made it clearer that in adult hypophosphatasia (HPP), how people feel and function may not match what a bone density scan shows. In a German study of 146 adults with genetically confirmed late-onset HPP, both physical and mental quality of life scores were reduced, and pain was common and disruptive to daily activities [3] . Measures like handgrip strength and a chair-rise test tracked with quality of life and pain, while bone density did not show the same relationship [3] .

Biochemistry and symptoms also moved together in this adult group. Lower alkaline phosphatase and lower bone-specific alkaline phosphatase were linked with worse quality of life and higher pain scores, while vitamin B6 levels (PLP) showed a non-significant visual trend in the opposite direction, with higher levels tending to occur alongside greater pain and pain interference [3] . The study also reported that genetic subgrouping did not explain differences in quality of life, suggesting that day-to-day impact cannot be predicted from genotype alone in this dataset [3] .

For patients, this study supports a simple idea: in adult HPP, tests that reflect day-to-day function and pain may be closer to the lived experience than bone density alone [3] . This does not change care by itself, but it adds weight to research efforts that measure outcomes people can feel, such as pain interference, fatigue-related limitations, and physical performance [3] .

What remains uncertain is how these relationships change over time, because the data were collected at one point rather than following people forward [3] . Even so, the findings help explain why someone can have major pain and reduced function even if a bone density scan does not look dramatically abnormal, and why lab markers like alkaline phosphatase may be discussed alongside symptoms in HPP research [3] .

This month included early signals about two patient-relevant situations: identifying overlooked adult HPP and recognizing medication-related fracture risk in someone who has HPP. A hospital-based review suggested that looking for persistently low alkaline phosphatase among orthopedic patients with fractures or muscle symptoms can uncover suspected cases, including one genetically confirmed diagnosis among the small number followed [4] . Separately, a single-patient report described atypical femoral fractures after zoledronic acid in an adult woman later confirmed to have HPP [5] .

In the orthopedic screening study, 8 of 2,392 adults (0.33%) met the authors criteria for suspected HPP based on persistently low alkaline phosphatase plus clinical review, and only 2 of these were followed further in the report [4] . The key point is not the exact percentage, but that low alkaline phosphatase was used as a practical trigger to consider HPP in a setting where fractures and musculoskeletal pain are common [4] .

The case report focused on what happened after one person with HPP received a bisphosphonate (zoledronic acid). The patient developed atypical femoral fractures, and later received teriparatide, after which spinal bone density increased by 10.5% over the reported interval, while radius bone density decreased in the same time window [5] . Because this is one person, it mainly illustrates what can occur rather than predicting what will happen for others [5] .

For patients and caregivers, these reports mainly matter as awareness-building rather than definitive evidence. The screening study supports the idea that repeatedly low alkaline phosphatase, especially alongside fractures or long-standing muscle symptoms, can be a meaningful clue that prompts further evaluation in research and clinical settings [4] . The case report adds to published caution that some osteoporosis drugs may not fit well with HPP biology, and it documents one persons fracture course and later bone density changes after teriparatide [5] .

What remains uncertain is how well the screening approach performs in different hospitals and age groups, since few suspected cases were confirmed in the report and follow-up was limited [4] . It is also unclear how broadly the fracture experience in the single case applies to other adults with HPP, but it provides a concrete example of why medication history is often discussed in HPP workups and research conversations [5] .

This month expanded the biological story of hypophosphatasia beyond bone mineralization by pointing to direct roles for TNAP (the enzyme affected in HPP) in teeth and muscle. In mice, removing Alpl only in the tooth-forming epithelium caused male-specific enamel hypomineralization and abnormal tooth-forming cells. Teeth from the modified mice were also more susceptible to acid erosion in a laboratory model, suggesting a role for TNAP in enamel development and resilience [6] . In a separate mouse model of HPP, enzyme replacement with efzimfotase alfa improved muscle mitochondrial respiration measurements toward normal levels, and human muscle samples from a few people with HPP showed abnormal-looking mitochondria under the microscope [7] .

The enamel study helps separate tooth effects from whole-body bone effects. The mice had normal circulating alkaline phosphatase and no clear skeletal differences, yet male animals showed disrupted enamel-forming cells and thinner, less mineralized enamel on imaging, along with greater erosion in an artificial caries model [6] . This supports the idea that TNAP activity inside the enamel organ itself can matter for enamel quality, at least in this animal system [6] .

The muscle study added an early mechanistic link between HPP and muscle symptoms that some people report, such as fatigue or weakness. In untreated HPP-model mice, maximal muscle respiration was far below wild-type, and efzimfotase alfa increased these respiration measures close to wild-type values while only partially improving bone mineralization in the same animals [7] . The human biopsy component was small (3 patients), but it offered a visual match to the idea of muscle energy problems by showing mitochondrial structural abnormalities [7] .

For patients, these studies mainly help explain why HPP can involve teeth and muscle in ways that are not fully captured by standard bone tests. The enamel work provides a biological reason that enamel quality could be affected directly by TNAP problems, and it raises a question about whether some effects could differ by sex, which will need confirmation beyond mice [6] . The muscle work supports the possibility that enzyme replacement could influence muscle energy function, but this is still early research and does not by itself show symptom improvement in people [7] .

What remains uncertain is how closely these animal and lab findings map onto the wide range of human HPP experiences. The enamel study cannot yet explain why males and females differed, and the muscle study did not include formal muscle strength or endurance testing in mice and had very limited human tissue data [6] . Even with these gaps, the studies give a clearer research direction: HPP biology may affect mineralization and energy use in specific tissues, not only the skeleton as a whole [7] .