Abdelhak Nouri’s family have responded to reports the 20-year-old had a heart condition that was detected by the Dutch FA in 2014 and documented on the player’s medical file at Ajax by saying they are shocked and greatly regret neither the governing body nor the club told the player’s parents at the time “to jointly agree on a follow-up process”.

Abdelhak, who was one of the most talented young players in the Netherlands, collapsed on the pitch during a pre-season friendly in Austria against Werder Bremen on 8 July and remains in a low level of consciousness in a hospital in Amsterdam after suffering serious and permanent brain damage.

The Nouri family say they had not suspected or been aware of any pre-existing condition at the time of the incident and discovered the apparent heart defect – identified by the Dutch FA (KNVB) during routine screening in April 2014 – only when they obtained the medical file that Ajax provided “after repeated and explicit requests”.

That document was passed on as part of an investigation being carried out on the family’s behalf by John Beer, a personal injury lawyer. Beer is looking at all aspects of the incident in Austria, including the level of care that Abdelhak received on the pitch after he collapsed.

The Dutch newspaper NRC Handelsblad claimed on Friday the KNVB informed Ajax in writing that there was a problem with Abdelhak’s heart. KNVB doctors reportedly evaluated the heart condition as harmless. However, the Nouri family say they were not told either verbally or in writing about the result of the heart screening. The NRC report does not specify the condition.

In a statement released on Saturday morning, the family say had they known about the problem with Abdelhak’s heart – he was only 17 when it was picked up by the KNVB on an echocardiogram – they “would have immediately insisted on thorough follow-up examinations, a second opinion and regular follow-up tests, in order to assess the nature and risks of such a condition in combination with his intensive sporting activities”.

NRC goes on to report that “according to one person involved, it was communicated verbally” to Abdelhak that he had a heart defect, although the Nouri family in their statement say they “give no credence to this”.

It is unclear whether there is any connection between the pre-existing heart defect and Abdelhak’s collapse. He was able to play for Holland age-group teams at European championships in 2016 and 2014, so the KNVB told NRC it “may be concluded” there was no danger to the player’s health.

Items placed by the Amsterdam hospital where the Ajax midfielder Abdelhak Nouri was receiving treatment in July. Photograph: Tobias Schwarz/AFP/Getty Images

The KNVB responded to the family’s statement by saying the player was told in 2014 and 2016 about his medical results. The governing body said it had complied with protocol and insisted it was under no obligation to tell Abdelhak’s parents. “We have informed Nouri of the results, in writing and verbally, as well as his club Ajax,” said a spokesperson for the KNVB, who claimed a medical specialist was present at both meetings with the player. “Since Nouri was over 16 years old at the time it was sufficient to inform only the footballer himself.”

The KNVB added: “We cannot say whether we have found a heart defect in him. We cannot make a statement about that. This is covered by medical professional confidentiality.”

Ajax did not want to comment on NRC’s report and a club spokesman said: “No substantive information is to be shared as it is a medical, and therefore confidential, file. In addition, our doctor has to adhere to professional confidentiality/doctor-patient privilege. We communicate directly with the Nouri family about matters concerning Abdelhak and not through the media.”

However, the club issued a statement in the wake of the Nouri family’s comments. “The Nouri family would like, just as Ajax do, to know precisely what happened with Abdelhak. It has been known to us for some time that they have engaged a lawyer, just as we have, to investigate further. We naturally fully cooperate with this. Everything that we have and know is available to them.”

The full statement from the Nouri family said: “Over the past six months, the family has heard from various doctors – mostly on an informal basis – that there may not have been an adequate response after Abdelhak collapsed on the football pitch. Before taking any further positions or drawing any conclusions, the family will await the investigation that is currently being carried out by personal injury lawyer Mr John Beer.

“The family would like to express, however, that it is very shocked by the news that a heart condition was detected as early as 2014 during a medical examination of Abdelhak by the KNVB. The family only recently learned about this when they read the medical file that Ajax provided to them – after repeated and explicit requests.

“The family is convinced that Abdelhak himself had no knowledge of this condition. If the family had been aware of the heart condition at an earlier stage, they would have immediately insisted on thorough follow-up examinations, a second opinion and regular follow-up tests, in order to assess the nature and risks of such a condition in combination with his intensive sporting activities.

“The NRC Handelsblad article states, quoting a ‘person involved’, that Abdelhak was informed of the heart condition in 2014. In the light of the information currently available, the family attaches no credence to this and notes that the parents of Abdelhak, who was 17 years old at the time, were never informed, either in writing or orally. In the family’s opinion both the KNVB and Ajax could have been expected to explicitly inform the parents about this and to jointly agree on a follow-up process. The family greatly regrets that this never happened.

“The family is also awaiting the results of the investigation and the outcome of the ongoing discussions with Ajax. No further statements will be made in the meantime. The media are requested politely but firmly not to contact the family.”